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【327732】2022年辽宁省盘锦市中考数学真题

时间:2025-01-20 20:06:25 作者: 字数:21365字
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绝密·启用前

2022年辽宁省盘锦市中考数学真题

题号

总分

得分





注意事项:

1.答题前填写好自己的姓名、班级、考号等信息

2.请将答案正确填写在答题卡上



评卷人

得分




一、选择题

1. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的倒数是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
D
6

2.如图是某几何体的三视图,该几何体是(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

3.下列运算正确的是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

4.某校开展安全知识竞赛,进入决赛的学生有20名,他们的决赛成绩如下表所示:

决赛成绩/

100

99

98

97

人数

3

7

6

4


则这20名学生决赛成绩的中位数和众数分别是(       
A
9898
B
9899
C
98.598
D
98.599

5.不等式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的解集在数轴上表示为(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

6.下列调查中,适合采用抽样调查的是(       
A
.了解神舟飞船的设备零件的质量情况
B
.了解一批袋装食品是否含有防腐剂
C
.全国人口普查
D
.企业招聘,对应聘人员进行面试

7.下列命题不正确的是(       
A
.经过直线外一点,有且只有一条直线与这条直线平行
B
.负数的立方根是负数
C
.对角线互相垂直的四边形是菱形
D
.五边形的外角和是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

8.如图,线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是半圆O的直径。分别以点A和点O为圆心,大于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长为半径作弧,两弧交于MN两点,作直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,交半圆O于点C,交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 于点E,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长是(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
B
4
C
6
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

9.《九章算术》是中国传统数学重要的著作,奠定了中国传统数学的基本框架,其中《盈不足》卷记载了一道有趣的数学问题:“今有共买物,人出八,赢三;人出七,不足四,问人数、物价各几何?”译文:“今有人合伙购物,每人出8钱,会多出3钱;每人出7钱,又差4钱,问人数,物价各多少?”设人数为x人,物价为y钱,根据题意,下面所列方程组正确的是(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

10.如图,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是边长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的正方形,点E,点F分别为边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中点,点O为正方形的中心,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,点P从点E出发沿 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 运动,同时点Q从点B出发沿 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 运动,两点运动速度均为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,当点P运动到点F时,两点同时停止运动,设运动时间为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,下列图像能正确反映出St的函数关系的是(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

评卷人

得分




二、填空题

11.目前,我国基本医疗保险覆盖已超过13.5亿人,数据13.5亿用科学记数法表示为____________

12.分解因式: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ____________

13. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 在一次函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的图像上,当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,则a的取值范围是____________

14.若关于x的方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 有两个不相等的实数根,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,则从满足条件的所有整数m中随机选取一个,恰好是负数的概率是____________

15.下图是根据甲、乙两城市一周的日均气温绘制的折线统计图,根据统计图判断本圈的日平均气温较稳定的城市是____________.(选填“甲”或“乙”)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

16.如图,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,以 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 为直径的 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 交边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> DE两点, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长是____________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

17.如图,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,点D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的中点,将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 绕点D逆时针旋转得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,当点A的对应点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 落在边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 上时,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的延长线上,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的面积是____________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

18.如图,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 为矩形, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,点E为边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 上一点,将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 沿 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 翻折,点C的对应点为点F,过点F <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的平行线交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 于点G,交直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 于点H.若点G是边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的三等分点,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长是____________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

评卷人

得分




三、解答题

19.先化简,再求值: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,其中 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

20.某学校为丰富课后服务内容,计划开设经典诵读,花样跳绳、电脑编程、倒画赏析、民族舞蹈五门兴趣课程.为了解学生对这五门兴趣课程的喜爱情况,随机抽取了部分学生进行问卷调查(要求每位学生只能选择门课程),并将调查结果绘制成如下两幅不完整的统计图.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
根据图中信息,完成下列问题:
(1)
本次调查共抽取了____________名学生;
(2)
补全条形统计图;
(3)
计算扇形统计图中“电脑编程”所对应扇形的圆心角度数;
(4)
若全校共有1200名学生,请估计选择“民族舞蹈”课程的学生人数;
(5)
在经典通读课前展示中,甲同学从标有A《出师表》、B《观沧海》、C《行路难》的三个签中随机抽取一个后放回,乙同学再随机抽取一个,请用列表或画树状图的方法,求甲乙两人至少有一人抽到A《出师表》的概率.

21.如图,平面直角坐标系 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是菱形,点Ay轴正半轴上,点B的坐标是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的图像经过点C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(1)
求反比例函数的解析式;
(2)
D在边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 上,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,过点D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 轴,交反比例函数的图像于点E,求点E的坐标.

22.某数学小组要测量学校路灯 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的顶部到地面的距离,他们借助皮尺、测角仅进行测量,测量结果如下:

测量项目

测量数据

A处测得路灯顶部P的仰角 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

D处测得路灯顶部P的仰角 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

测角仪到地面的距离

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

两次测量时测角仪之间的水平距离

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>


计算路灯顶部到地面的距离 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 约为多少米?(结果精确到0.1米.参考数据; <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

23.如图,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是正方形,点A,点B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 上,边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的延长线交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 于点E,对角线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的延长线交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 于点F,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 并延长至点G,使 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(1)
求证: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 相切;
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的半径为1,求 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长.

24.某商场新进一批拼装玩具,进价为每个10元,在销售过程中发现.,日销售量y(个)与销售单价x(元)之间满足如图所示的一次函数关系.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(1)
yx的函数关系式(不要求写出自变量x的取值范围);
(2)
若该玩具某天的销售利润是600元,则当天玩具的销售单价是多少元?
(3)
设该玩具日销售利润为w元,当玩具的销售单价定为多少元时,日销售利润最大?最大利润是多少元?

25. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,点D在线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 上,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 并延长至点E,使 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,过点E <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,交直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 于点F
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(1)
如图1,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,请用等式表示 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的数量关系:____________
(2)
如图2.若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,完成以下问题:
当点D,点F位于点A的异侧时,请用等式表示 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 之间的数量关系,并说明理由;
当点D,点F位于点A的同侧时,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,请直接写出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长.

26.如图,抛物线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> x轴交于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 两点(AB的左侧),与y轴交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,点P在抛物线上,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(1)
求抛物线的解析式;
(2)
如图1,若点P在第四象限,点D在线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 上,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 并延长交x轴于点E,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,记 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 时,求点P的坐标;
(3)
如图2,若点P在第二象限,点F为抛物线的顶点,抛物线的对称轴l与线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 交于点G,当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 时,求点P的横坐标.

参考答案

1.A

【解析】
根据互为倒数两个数的乘积等于1进行解答即可得.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的倒数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故选A

2.C

【解析】
由主视图和左视图确定是柱体,锥体还是球体,再由俯视图确定具体形状.
解:主视图和左视图都是等腰三角形,那么此几何体为锥体,由俯视图为圆,可得此几何体是圆锥.
故选:C

3.B

【解析】
由同底数幂乘法、积的乘方、负整数指数幂的乘法、合并同类项,分别进行判断,即可得到答案.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,故A错误;
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,故B正确;
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,故C错误;
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 不能合并,不D错误;
故选:B

4.D

【解析】
根据众数,中位数的定义计算选择即可.
∵99
出现的次数最多,7次,
众数为99
中位数是第10个,11个数据的平均数即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故选D

5.C

【解析】
先求得不等式的解集为x≤4,根据等号判定圆圈为实心,选择即可.
不等式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的解集为x≤4
数轴表示为:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故选C

6.B

【解析】
调查方式的选择需要将普查的局限性和抽样调查的必要性结合起来,具体问题具体分析,普查结果准确,所以在要求精确、难度相对不大,实验无破坏性的情况下应选择普查方式,当考查的对象很多或考查会给被调查对象带来损伤破坏,以及考查经费和时间都非常有限时,普查就受到限制,这时就应选择抽样调查.
解:A、了解神舟飞船的设备零件的质量情况,非常重要,适合普查;故A不符合题意;
B
、了解一批袋装食品是否含有防腐剂,具有破坏性,适合抽样调查;故B符合题意;
C
、全国人口普查,非常重要,适合普查,故C不符合题意;
D
、企业招聘,对应聘人员进行面试,工作量比较小,适合普查;故D不符合题意;
故选:B

7.C

【解析】
由平行线公理、立方根的定义、菱形的判定定理、多边形的外角和,分别进行判断,即可得到答案.
解:A、经过直线外一点,有且只有一条直线与这条直线平行;故A正确;
B
、负数的立方根是负数;故B正确;
C
、对角线互相垂直的平行四边形是菱形,故C错误;
D
、五边形的外角和是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,故D正确;
故选:C

8.A

【解析】
根据作图知CE垂直平分AC,即可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,根据圆的半径得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,根据圆周角的推论得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,根据勾股定理即可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
解:根据作图知CE垂直平分AC
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
线段AB是半圆O的直径,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中,根据勾股定理得,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故选A

9.B

【解析】
根据译文可知“人数×8-3=钱数和人数×7+4=钱数”即可列出方程组.
解:由题意可得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故选:B

10.D

【解析】
0≤t≤11t≤2两种情形,确定解析式,判断即可.
0≤t≤1时,∵正方形ABCD 的边长为2,点O为正方形的中心,
直线EO垂直BC
P到直线BC的距离为2-tBQ=t
S= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
1t≤2时,∵正方形ABCD 的边长为2,点F分别为边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中点,点O为正方形的中心,
直线OFBC
P到直线BC的距离为1BQ=t
S= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故选D

11. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
用移动小数点的方法确定a值,根据整数位数减一原则确定n值,最后写成 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的形式即可.
∵13.5
亿= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

12. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
先提取公因数y,再利用完全平方公式进行二次分解.完全平方公式:(a±b2=a2±2ab+b2
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

13.a2

【解析】
根据一次函数的性质,建立不等式计算即可.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
a-20
a2
故答案为:a2

14. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
根据题意,由关于x的一元二次方程的根的判别式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,可计算 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,再结合 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 可知 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,进而推导满足条件的所有整数为-3-2-1012共计6个,其中负数有3个,由简单概率的计算公式即可得出结果.
解:根据题意,关于x的方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 有两个不相等的实数根,
故该一元二次方程的根的判别式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
又∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
满足条件的所有整数为-3-2-1012共计6个,其中负数有-3-2-1共计3个,
满足条件的所有整数m中随机选取一个,恰好是负数的概率是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

15.

【解析】
根据方差的性质:方差越大,数据波动越大;方差越小,数据波动越小.,判断即可.
解:由图知,乙的气温波动较小,故本周的日平均气温稳定的是乙城市.
故答案为:乙.

16. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
连接OEOD,根据等腰三角形的性质,求得∠DOE=50°,半径为1,代入弧长公式计算即可.
连接OEOD
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> OB=ODOA=OE
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
∴∠
B=∠ODB =65°,∠A=∠OEA =50°
∴∠
BOD =50°,∠AOE =80°
∴∠
DOE=50°,半径为1
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

17. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
先证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是等边三角形,再证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,再利用直角三角形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 角对应的边是斜边的一般分别求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,再利用勾股定理求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,从而求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的面积.
解:如下图所示,设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 交于点O,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的中点, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> , <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的角平分线, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是等边三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

18. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,根据题意可得四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是平行四边形,证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,等面积法求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,勾股定理求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长,进而即可求解.
如图,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是平行四边形
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 折叠
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是矩形
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
如图,当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 时,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
同理可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

19. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
根据分式的运算法则“除以一个数等于乘以它的倒数”把除法改写成乘法;利用平方差公式和完全平方公式将分式的分子分母分别因式分解;约分化简后,求x的值;去掉绝对值符号时注意正负,正数的绝对值是他本身,负数的绝对值是它的相反数,最后将x的值代入原式.
解:原式= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> = <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 原式= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> = <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> = <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

20.(1)300
(2)
见详解
(3)120°
(4)200
(5)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
1)由国画赏析的人数除以所占的百分比,即可得到答案;
2)利用抽取的总人数减去其他项目的人数,再补全条形图即可;
3)先求电脑编程所占百分比,然后乘以360°,即可得到答案;
4)先求民族舞蹈所占百分比,然后乘以1200,即可得到答案;
5)先列出表格得出所有等可能的结果数,再根据概率公式即可得出答案.
(1)
解:本次调查共抽取的学生人数为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> (人);
故答案为:300
(2)
解:根据题意,
花样跳绳的人数为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> (人);
补全条形图如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(3)
解:根据题意,
电脑编程”所对应扇形的圆心角度数为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(4)
解:全校选择“民族舞蹈”课程的学生人数为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> (人);
(5)
解:列表如下:


A

B

C

A

AA

BA

CA

B

AB

BB

CB

C

AC

BC

CC


共有9种等可能的结果,其中甲乙两人至少有一人抽到A5种,
所以两人至少有一人抽到A《出师表》的概率为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

21.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> );

【解析】
1)过点BBFy轴,垂足为F,设点A为(0m),根据菱形的性质和勾股定理求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,然后求出点C的坐标,即可求出解析式;
2)作DGx轴,CHx轴,垂足分别为GH,先证明△ODG∽△OCH,求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,然后得到点D的纵坐标,再求出点E的坐标即可.
(1)
解:根据题意,过点BBFy轴,垂足为F,如图:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是菱形,
设点A为(0m),
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
在直角△ABF中,由勾股定理,则
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
C的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
把点C代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
反比例函数的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(2)
解:作DGx轴,CHx轴,垂足分别为GH,如图,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
DGCH
∴△
ODG∽△OCH
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
C的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
D的纵坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 轴,
E的纵坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
E的坐标为( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> );

22.3.5

【解析】
延长DA,交PE于点F,则DFPE,先得到四边形ABCDCDFE是矩形,然后由解直角三角形求出AF的长度,再求出PF的长度,即可求出答案.
解:如图:延长DA,交PE于点F,则DFPE
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
四边形ABCD是平行四边形,
ABBC
四边形ABCD是矩形,
同理:四边形CDFE是矩形;
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
在直角△PDF中,有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
在直角△PAF中,有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> (米);
路灯顶部到地面的距离 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 约为3.5米.

23.(1)见解析
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
(1)
连接BE,根据四边形ABCD是正方形,得到∠BAE=90°,从而得到BE是圆O的直径,结合∠BAF+∠EAF=90°,∠EAF=∠EBF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,证明∠FBG+∠EBF=90°即可.
2)连接OAOF,证明∠FED=45°,从而证明∠AOF=90°,实施勾股定理计算即可.
(1)
连接BE
四边形ABCD是正方形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
∴∠
BAE=90°
BE是圆O的直径,
∵∠
BAF+∠EAF=90°,∠EAF=∠EBF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
∴∠
FBG+∠EBF=90°
∴∠
OBG=90°
BG是圆O的切线.
(2)
如图,连接OAOF
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
四边形ABCD是正方形,BE是圆的直径,
∴∠
EFD=90°,∠FDE=45°
∴∠
FED=45°
∴∠
AOF=90°
OA=OF=1
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
AF= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> AF=- <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> (舍去).

24.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(2)40
元或20元;
(3)
当玩具的销售单价定为30元时,日销售利润最大;最大利润是800元;

【解析】
1)直接由待定系数法,即可求出一次函数的解析式;
2)根据题意,设当天玩具的销售单价是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 元,然后列出一元二次方程,解方程即可求出答案;
3)根据题意,列出w <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的关系式,然后利用二次函数的性质,即可求出答案.
(1)
解:由图可知,设一次函数的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
把点(2550)和点(3530)代入,得
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
一次函数的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(2)
解:根据题意,设当天玩具的销售单价是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 元,则
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
当天玩具的销售单价是40元或20元;
(3)
解:根据题意,则
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
整理得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 有最大值,最大值为800
当玩具的销售单价定为30元时,日销售利润最大;最大利润是800元.

25.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(2)①
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ;② <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
1)过点CCGABG,先证明△EDF≌△CDG,得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,然后等腰三角形的性质和含30度直角三角形的性质,即可求出答案;
2)①过点CCHABH,与(1)同理,证明△EDF≌△CDH,然后证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是等腰直角三角形,即可得到结论;
过点CCGABG,与(1)同理,得△EDF≌△CDG,然后得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是等腰直角三角形,利用勾股定理解直角三角形,即可求出答案.
(1)
解:过点CCGABG,如图,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
∴△
EDF≌△CDG
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(2)
解:①过点CCHABH,如图,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
与(1)同理,可证△EDF≌△CDH
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是等腰直角三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是等腰直角三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
如图,过点CCGABG
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
与(1)同理可证,△EDF≌△CDG
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
当点F在点AD之间时,有
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
与①同理,可证 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是等腰直角三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
当点D在点AF之间时,如图:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
与①同理,可证 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 是等腰直角三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
综合上述,线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 的长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

26.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(3)
P的横坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>

【解析】
1)将将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 两点代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 即可求解;
2)设点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,由 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 即可求解;
3)作CElPQBCPNx轴,连接PCx轴于点H,设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> PC的表达式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,由PC代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 得,PC的表达式,由 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 可表示PQPB,分别求EFCF,由 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> PQBCCEl,证 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 即可求解;
(1)
解:将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 两点代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 得,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
抛物线的解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 可得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
设点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> (舍去)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
(3)
如图,作CElPQBCPNx轴,连接PCx轴于点H
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> PC的表达式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
PC代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 得,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
PC的表达式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
y=0代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
由题可知, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> 得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> PQBCCEl
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/990/" title="辽宁省" class="c1" target="_blank">辽宁省</a> <a href="/tags/992/" title="盘锦" class="c1" target="_blank">盘锦</a> <a href="/tags/1122/" title="辽宁" class="c1" target="_blank">辽宁</a> (舍去).