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【327720】2022年江苏省徐州市中考数学真题

时间:2025-01-20 20:04:46 作者: 字数:17547字
简介:

绝密·启用前

2022年江苏省徐州市中考数学真题

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.﹣3的绝对值是(  )
A
3
B
.﹣3
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

2.下列图案是轴对称图形但不是中心对称图形的是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

3.要使得式子 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 有意义,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的取值范围是(    )
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

4.下列计算正确的是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

5.如图,已知骰子相对两面的点数之和为7,下列图形为该骰子表面展开图的是(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

6.我国近十年的人口出生率及人口死亡率如图所示.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
已知人口自然增长率=人口出生率—人口死亡率,下列判断错误的是(       
A
.与2012年相比,2021年的人口出生率下降了近一半
B
.近十年的人口死亡率基本稳定
C
.近五年的人口总数持续下降
D
.近五年的人口自然增长率持续下降

7.将一枚飞镖任意投掷到如图所示的正六边形镖盘上,若飞镖落在镖盘上各点的机会相等,则飞镖落在阴影区域的概率为(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

8.如图,若方格纸中每个小正方形的边长均为1,则阴影部分的面积为(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
A
5
B
6
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

评卷人

得分




二、填空题

9.因式分解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ______

10.正十二边形每个内角的度数为

11.方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的解是x=__

12.我国2021年粮食产量约为13700亿斤,创历史新高,其中13700亿斤用科学记数法表示为________亿斤.

13.如图,ABC点在圆O上, 若∠ACB=36°, 则∠AOB=________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

14.如图,圆锥的母线AB6,底面半径CB2,则其侧面展开图扇形的圆心角α_______
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

15.若一元二次方程x2xc0没有实数根,则c的取值范围是________

16.如图,将矩形纸片ABCD沿CE折叠,使点B落在边AD上的点F处.若点E在边AB上,AB3BC5,则AE________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

17.若一次函数ykxb的图像如图所示,则关于kx <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> b0的不等式的解集为________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

18.若二次函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的图象上有且只有三个点到x轴的距离等于m,则m的值为________

评卷人

得分




三、解答题

19.计算:
(1)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

20.1)解方程: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)解不等式组: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

21.如图,将下列3张扑克牌洗匀后数字朝下放在桌面上.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(1)
从中随机抽取1张,抽得扑克牌上的数字为3的概率为
(2)
从中随机抽取2张,用列表或画树状图的方法,求抽得2张扑克牌的数字不同的概率.

22.《孙子算经》是中国古代重要的数学著作,该书第三卷记载:“今有兽六首四足,禽四首二足,上有七十六首,下有四十六足,问禽、兽各几何?”译文:今有一种64脚的兽与一种42脚的鸟,若兽与鸟共有76个头与46只脚.问兽、鸟各有多少?
根据译文,解决下列问题:
(1)
设兽有x个,鸟有y只,可列方程组为
(2)
求兽、鸟各有多少.

23.如图,在平行四边形ABCD中,点EF在对角线BD上,且BEDF.求证:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(1)△
ABE≌△CDF
(2)
四边形AECF是平行四边形.

24.如图,如图,点ABC在圆O上, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,点OBD上.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(1)
判断直线AD与圆O的位置关系,并说明理由;
(2)
若圆的半径为6,求图中阴影部分的面积.

25.如图,在△ABC中,∠BAC90°ABAC12,点P在边AB上,DE分别为BCPC的中点,连接DE.过点EBC的垂线,与BCAC分别交于FG两点.连接DG,交PC于点H
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(1)∠
EDC的度数为
(2)
连接PG,求△APG 的面积的最大值;
(3)
PEDG存在怎样的位置关系与数量关系?请说明理由;
(4)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的最大值.

评卷人

得分




四、其他

26.如图,下列装在相同的透明密封盒内的古钱币,其密封盒上分别标有古钱币的尺寸及质量,例如:钱币“文星高照”密封盒上所标“”是指该枚古钱币的直径为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,厚度为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,质量为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .已知这些古钱币的材质相同.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
根据图中信息,解决下列问题.
(1)
5枚古钱币,所标直径的平均数是  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,所标厚度的众数是  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,所标质量的中位数是 g
(2)
由于古钱币无法从密封盒内取出,为判断密封盒上所标古钱币的质量是否有错,桐桐用电子秤测得每枚古钱币与其密封盒的总质量如下:

名称

文星高照

状元及第

鹿鹤同春

顺风大吉

连中三元

总质量/g

58.7

58.1

55.2

54.3

55.8


请你应用所学的统计知识,判断哪枚古钱币所标的质量与实际质量差异较大,并计算该枚古钱币的实际质量约为多少克.

27.如图,公园内有一个垂直于地面的立柱 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,其旁边有一个坡面 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,坡角 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .在阳光下,小明观察到在地面上的影长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,在坡面上的影长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .同一时刻,小明测得直立于地面长的木杆的影长为(其影子完全落在地面上).求立柱的高度.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

28.如图,一次函数的图象与反比例函数的图象 交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .与轴交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .与轴交于点轴于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,点关于直线的对称点为点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(1)
点是否在这个反比例函数的图象上? 请说明理由;
(2)
连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,若四边形为正方形.
kb的值;
若点Py 轴上,当|PEPB|最大时,求点P的坐标.

参考答案

1.A

【解析】
根据绝对值的运算规律:一个正数的绝对值是它本身;一个负数的绝对值是它的相反数;0的绝对值是0.即可得出结果.
解:﹣3的绝对值是3
故选:A

2.C

【解析】
根据轴对称图形和中心对称图形的定义:如果一个平面图形沿一条直线折叠,直线两旁的部分能够互相重合,这个图形就叫做轴对称图形;中心对称图形的定义:把一个图形绕着某一个点旋转180°,如果旋转后的图形能够与原来的图形重合,那么这个图形叫做中心对称图形,这个点就是它的对称中心,进行逐一判断即可.
解:A、是中心对称图形,是轴对称图形,故A选项不合题意;
B
、是中心对称图形,是轴对称图形,故B选项不合题意;
C
、是轴对称图形,不是中心对称图形,故C选项不合题意;
D
、是中心对称图形,是轴对称图形,故D选项不合题意;
故选:C

3.B

【解析】
根据二次根式有意义,被开方数大于等于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,列不等式求解.
解:根据题意,得
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故选:B

4.A

【解析】
根据同底数幂的乘法,同底数幂的除法,合并同类项,积的乘方逐项分析判断即可求解.
解:A.  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,故该选项正确,符合题意;       
B.  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,故该选项不正确,不符合题意;
C.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,故该选项不正确,不符合题意;       
D.  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,故该选项不正确,不符合题意;
故选A

5.D

【解析】
根据骰子表面展开后,其相对面的点数之和是7,逐项判断即可作答.
A
项,2的对面是4,点数之和不为7,故A项错误;
B
项,2的对面是6,点数之和不为7,故B项错误;
C
项,2的对面是6,点数之和不为7,故C项错误;
D
项,1的对面是62的对面是53的对面是4,相对面的点数之和都为7,故D项正确;
故选:D

6.C

【解析】
根据折线统计图逐项分析判断即可求解.
解:A. 2012年相比,2021年的人口出生率下降了近一半,故该选项正确,不符合题意;
B.
近十年的人口死亡率基本稳定,故该选项正确,不符合题意;
C.
近五年的人口总数持续上升,只是自然增长率在变小,故该选项不正确,符合题意;
D.
近五年的人口自然增长率持续下降,故该选项正确,不符合题意.
故选C

7.B

【解析】
如图,将阴影部分分割成图形中的小三角形,令小三角形的面积为a,分别表示出阴影部分的面积和正六边形的面积,根据概率公式求解即可.
解:如图,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
根据题意得:图中每个小三角形的面积都相等,
设每个小三角形的面积为a,则阴影的面积为6a,正六边形的面积为18a
将一枚飞镖任意投掷到镖盘上,飞镖落在阴影区域的概率为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故选:B

8.C

【解析】
证明ABE∽△CDE,求得AECE,再根据三角形的面积关系求得结果.
解:∵CDAB
∴△
ABE∽△CDE
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> =2
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故选:C

9. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ##x-1)(x+1

【解析】
平方差公式: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 直接利用平方差公式分解因式即可.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

10. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
首先求得每个外角的度数,然后根据外角与相邻的内角互为邻补角即可求解.
试题正十二边形的每个外角的度数是: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> =30°
则每一个内角的度数是:180°﹣30°=150°
故答案为150°

11.6

【解析】
试题两边同乘以x(x-2)可得:3(x-2)=2x,解得:x=6,经检验:x=6是方程的根.

12. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
用科学记数法表示较大的数时,一般形式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,其中 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 为整数.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

13.72°##72

【解析】
利用一条弧所对的圆周角等于它所对的圆心角的一半即可得出结论.
解:∵∠ACB= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> AOB,∠ACB=36°
∴∠
AOB=2×∠ACB=72°
故答案为:72°

14.120°

【解析】
根据圆锥的侧面展开图为一扇形,这个扇形的弧长等于圆锥底面的周长,扇形的半径等于圆锥的母线长和弧长公式得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 2π•2,然后解方程即可.
解:根据题意得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 2π•2
解得α120
即侧面展开图扇形的圆心角为120°
故答案为120°

15. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ## <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
根据一元二次方程根的判别式进行判断即可求解.
解:∵一元二次方程x2xc0没有实数根,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

16. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ## <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
由折叠性质可得CF=BC=5BE=EF,由矩形性质有CD=AB=3BC=AD=5,勾股定理求得DFAF.设BE=EF=x,则AE=AB-BE,在直角三角形AEF中,根据勾股定理,建立方程,解方程即可求解.
解:由折叠性质可得CF=BC=5BE=EF
由矩形性质有CD=AB=3BC=AD=5
∵∠
D=90°
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
所以 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
所以 BE=EF=x,则AE=AB-BE=3-x,在直角三角形AEF:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

17. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
根据函数图像得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,然后解一元一次不等式即可求解.
解:∵根据图像可知ykxb <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 轴交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

18.4

【解析】
由抛物线解析式可得抛物线对称轴为直线x=1,顶点为(1-4),由图象上恰好只有三个点到x轴的距离为m可得m=4
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
抛物线开口向上,抛物线对称轴为直线x=1,顶点为(1-4),
顶点到x轴的距离为4
函数图象有三个点到x轴的距离为m
m=4
故答案为:4

19.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1)先用乘方、绝对值、负整数次幂、算术平方根化简,然后再计算即可;
2)按照分式混合运算法则计算即可.
1
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

20.1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ;(2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1)根据配方法解一元二次方程即可求解;
2)分别求出每一个不等式的解集,根据口诀:同大取大、同小取小、大小小大中间找、大大小小找不到确定不等式组的解集.
1)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解不等式①得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解不等式②得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
不等式组的解集为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

21.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1)直接由概率公式求解即可;
2)列表或画树状图,共有6种等可能的结果,其中抽到2张扑克牌的数字不同的结果有4种,再由概率公式求解即可.
1
解:根据题意,3张扑克牌中,数字为2的扑克牌有一张,数字为3的扑克牌有两张,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 从中随机抽取1张,抽得扑克牌上的数字为3的概率为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2
解:画树状图如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
如图,共有6种等可能的结果,其中抽到2张扑克牌的数字不同的结果有4种,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 抽得2张扑克牌的数字不同的概率为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

22.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(2)
兽有8只,鸟有7只.

【解析】
1)根据“兽与鸟共有76个头与46只脚”,即可得出关于xy的二元一次方程组;
2)解方程组,即可得出结论.
1
解:∵兽与鸟共有76个头,
∴6
x+4y=76
兽与鸟共有46只脚,
∴4
x+2y=46
可列方程组为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2
解:原方程组可化简为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
由②可得y=23-2x
将③代入①得3x+223-2x=38
解得x=8
y=23-2x=23-2×8=7
答:兽有8只,鸟有7只.

23.(1)见解析
(2)
见解析

【解析】
1)根据平行四边形的性质可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,根据平行线的性质可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,结合已知条件根据SAS即可证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,根据邻补角的意义可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,根据一组对边平行且相等即可得出.
1
证明:解:∵四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是平行四边形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> SAS);
2
证明:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
四边形AECF是平行四边形

24.(1)直线AD与圆O相切,理由见解析
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1)连接OA,根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> AB=AD,可得∠DBC=∠ABD=∠D=30°,从而得到∠BAD=120°,再由OA=OB,可得∠BAO=∠ABD=30°,从而得到∠OAD=90°,即可求解;
2)连接OC,作OHBCH,根据垂径定理可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,进而得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,再根据阴影部分的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,即可求解.
1
解:直线AD与圆O相切,理由如下:
如图,连接OA
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
∴∠
D=∠DBC
AB=AD
∴∠
D=∠ABD
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
∴∠
DBC=∠ABD=∠D=30°
∴∠
BAD=120°
OA=OB
∴∠
BAO=∠ABD=30°
∴∠
OAD=90°
OAAD
OA是圆的半径,
直线AD与园O相切,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2
解:如图,连接OC,作OHBCH
OB=OC=6
∴∠
OCB=∠OBC=30°
∴∠
BOC=120°
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
扇形BOC的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
阴影部分的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

25.(1)45°
(2)9
(3)
PE=DG,理由见解析
(4)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1)先说明∠B=45°,再说明DE是△CBP的中位线可得DE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> BP,然后由平行线的性质即可解答;
2)先说明△EDF和△GFC是等腰直角三角形可得DF=EF= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> GF=CF= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ;设AP=x,则BP=12-xBP=12-x=2DE,然后通过三角形中位线、勾股定理、线段的和差用x表示出AG,再根据三角形的面积公式列出表达式,最后运用二次函数求最值即可;
3)先证明△GFD≌△CFE,可得DG=CE,进而可得PE=DG;由△GFD≌△CFE可得∠ECF=∠DGF,进而得到∠GHE=∠CFE=90°,即可说明DGPE的位置关系;
4)先说明△CEF∽△CDH得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,进而得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,然后将已经求得的量代入可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,然后根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 求最值即可.
1
解:∵在△ABC中,∠BAC90°ABAC12
∴∠
B=∠ACB=45°
DE分别为BCPC的中点
DE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> BPDE= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
∴∠
EDC=B=45°
2
解:如图:连接PG
∵∠EDC=∠ACB=45°GFDC
∴△EDF和△GFC是等腰直角三角形
DF=EF= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> GF=CF= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
AP=x,则BP=12-xBP=12-x=2DE
DE= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> EF= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
RtAPC
PC= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
CE= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
RtEFC
FC=FG= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
CG= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> CF= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
AG=12-CG=12- <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> = <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
SAPG= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
所以当x=6时,SAPG有最大值9
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
3
解:DG=PEDGPE,理由如下:
DF=EF,∠CFE=∠GFDGF=CF
∴△GFD≌△CFE(SAS)
DG=CE
EPC的中点
PE=CE
PE=DG
∵△
GFD≌△CFE
∴∠ECF=∠DGF
∵∠CEF=∠PEG
∴∠GHE=∠EFC=90°,即DGPE
4
解:∵△GFD≌△CFE
∴∠CEF=∠CDH
又∵∠ECF=∠DCH
∴△CEF∽△CDH
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
FC= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> CE= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> CD= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的最大值为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

26.(1)
(2)

【解析】

27.

【解析】

28.(1)
(2)

【解析】