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【327767】2022年四川省广安市中考数学真题

时间:2025-01-20 20:13:18 作者: 字数:20565字
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2022年四川省广安市中考数学真题

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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.从百年前的“奥运三问”到今天的“双奥之城”,2022年中国与奥运再次牵手,2022年注定是不平凡的一年.数字2022的倒数是(  )
A
2022
B
.﹣2022
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

2.下列运算中,正确的是(  )
A
3a2 +2a2 =5a4
Ba9÷a3=a3
C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
D
.(﹣3x23=﹣27x6

3.北斗卫星导航系统是我国着眼于经济社会发展需要,自主建设、独立运行的卫星导航系统,属于国家重要空间基础设施.截至20223月,北斗高精度时空服务覆盖全球百余个国家和地区,累计服务超11亿人口,请将11亿用科学记数法表示为(  )
A
1.1×108
B1.1×109
C1.1×1010
D1.1×1011

4.如图所示,几何体的左视图是(  )
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

5.下列说法正确的是(  )
A
.对角线相等的四边形是矩形.
B
.相似三角形的面积的比等于相似比.
C
.方差越大,数据的波动越大;方差越小,数据的波动越小.
D
.过一点有且只有一条直线与已知直线平行.

6.某校九年级8个班的同学积极参与“一木一环保”捐书活动,以班为单位自愿捐赠废旧书本,经统计,每个班捐赠的书本质量(单位:kg)如下:2630282830323430,则这组数据的中位数和众数分别为(  )
A
3030
B
2928
C
2830
D
3028

7.在平面直角坐标系中,将函数y=3x +2的图象向下平移3个单位长度,所得的函数的解析式是(  )
A
y=3x+5
B
y=3x﹣5
C
y=3x+1
D
y=3x﹣1

8.如图,菱形ABCD的边长为2,点P是对角线AC上的一个动点,点EF分别为边ADDC的中点,则PE + PF的最小值是(  )
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
A
2
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
C
1.5
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

9.蒙古包可以近似地看作由圆锥和圆柱组成.下图是一个蒙古包的示意图,底面圆半径DE=2m,圆锥的高AC=1.5m,圆柱的高CD=2.5m,则下列说法错误的是(  )
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
A
.圆柱的底面积为4πm2
B.圆柱的侧面积为10πm2
C.圆锥的母线AB长为2.25m
D
.圆锥的侧面积为5πm2

10.已知抛物线y=ax2 +bx +c的对称轴为x=1,与x轴正半轴的交点为A30),其部分图象如图所示,有下列结论:①abc 0;②2c﹣3b 0;③5a +b+2c=0;④若B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> y1)、C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> y2)、D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> y3)是抛物线上的三点,则y1y2y3.其中正确结论的个数有(  )
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
A
1
B
2
C
3
D
4

评卷人

得分




二、填空题

11.比较大小: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> __________3(填“>”、“<”或“=”)

12.已知a+b=1,则代数式a2b2 +2b+9的值为________

13.若点Pm+1m)在第四象限,则点Q(﹣3m+2)在第________象限.

14.若(a﹣32+ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> =0,则以ab为边长的等腰三角形的周长为________

15.如图是抛物线形拱桥,当拱顶离水面2米时,水面宽6米,水面下降________米,水面宽8米.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

16.如图,四边形ABCD是边长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的正方形,曲线DA1B1C1D1A2是由多段90°的圆心角所对的弧组成的.其中,弧DA1的圆心为A,半径为AD;弧A1B1的圆心为B,半径为BA1;弧B1C1的圆心为C,半径为CB1;弧C1D1的圆心为D,半径为DC1.弧DA1、弧A1B1、弧B1C1、弧C1D1的圆心依次按点ABCD循环,则弧C2022D2022的长是___________(结果保留π).
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

评卷人

得分




三、解答题

17.计算: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

18.先化简: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,再从0123中选择一个适合的数代人求值.

19.如图,一次函数y=kx+bkb为常数,k≠0)的图象与反比例函数y= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> m为常数,m≠0)的图象在第二象限交于点A(﹣43),与y轴负半轴交于点B,且OA=OB
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(1)
求反比例函数和一次函数的解析式.
(2)
根据图象直接写出当x0时,不等式kx+b <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的解集.

20.如图,点D是△ABC外一点,连接BDADADBC交于点O.下列三个等式:①BC=AD;②∠ABC=∠BAD;③AC= BD.请从这三个等式中,任选两个作为已知条件,剩下的一个作为结论,组成一个真命题,将你选择的等式或等式的序号填在下面对应的横线上,然后对该真命题进行证明.
已知:
求证:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

21.某校在开展线上教学期间,为了解七年级学生每天在家进行体育活动的时间(单位:h),随机调查了该年级的部分学生.根据调查结果,绘制出如下的扇形统计图1和条形统计图2,请根据相关信息,解答下列问题:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(1)
本次随机调查的学生共有 人,图1m的值为
(2)请补全条形统计图
(3)
体育活动时间不足1小时的四人中有3名女生A1A2A31名男生B.为了解他们在家体育活动的实际情况,从这4人中随机抽取2人进行电话回访,请用列表法或画树状图法,求恰好抽到两名女生的概率

22.某企业下属AB两厂向甲乙两地运送水泥共520吨,A厂比B厂少运送20吨,从A厂运往甲乙两地的运费分别为40/吨和35/吨,从B厂运往甲乙两地的运费分别为28/吨和25/吨.
(1)
AB两厂各运送多少吨水泥?
(2)
现甲地需要水泥240吨,乙地需要水泥280吨.受条件限制,B厂运往甲地的水泥最多150吨.设从A厂运往甲地a吨水泥,AB两厂运往甲乙两地的总运费为w元.求wa之间的函数关系式,请你为该企业设计一种总运费最低的运输方案,并说明理由

23.八年级二班学生到某劳动教育实践基地开展实践活动,当天,他们先从基地门口A处向正北方向走了450米,到达菜园B处锄草,再从B处沿正西方向到达果园C处采摘水果,再向南偏东37°方向走了300米,到达手工坊D处进行手工制作,最后从D处回到门口A处,手工坊在基地门口北偏西65°方向上.求菜园与果园之间的距离.(结果保留整数)参考数据:sin65°≈ 0.91cos65°≈0.42tan65°≈2.14sin37°≈ 0.60cos37°≈ 0.80tan37°≈0.75
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

24.数学活动课上,张老师组织同学们设计多姿多彩的几何图形, 下图都是由边长为1的小等边三角形构成的网格,每个网格图中有3个小等边三角形已涂上阴影,请同学们在余下的空白小等边三角形中选取一个涂上阴影,使得4个阴影小等边三角形组成一个轴对称图形或中心对称图形,请画出4种不同的设计图形.规定:凡通过旋转能重合的图形视为同一种图形)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

25.如图,AB为⊙O的直径,DE是⊙O上的两点,延长AB至点C,连接CD,∠BDC=∠BAD
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(1)
求证:CD是⊙O的切线.
(2)
tan∠BED= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> AC=9,求⊙O的半径.

26.如图,在平面直角坐标系中,抛物线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> a≠0)的图象与x轴交于AC两点,与y轴交于点B,其中点B坐标为(0,-4),点C坐标为(20).
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(1)
求此抛物线的函数解析式.
(2)
D是直线AB下方抛物线上一个动点,连接ADBD,探究是否存在点D,使得△ABD的面积最大?若存在,请求出点D的坐标;若不存在,请说明理由.
(3)
P为该抛物线对称轴上的动点,使得△PAB为直角三角形,请求出点P的坐标.

参考答案

1.D

【解析】
根据倒数的定义,即可求解.
解:2022的倒数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
故选:D

2.D

【解析】
根据合并同类项,同底数幂的除法,二次根式的加法,积的乘方运算,逐项分析判断即可求解.
解:A. 3a2 +2a2 =5 a 2,故该选项不正确,不符合题意;
B.
a9÷a3=a6,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/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,故该选项不正确,不符合题意;
D.
(﹣3x23=﹣27x6,故该选项正确,符合题意;
故选D

3.B

【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/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,其中 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 为整数.
解:11亿 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
故选:B

4.B

【解析】
根据从正面看的图形是主视图,从左面看到的图形是左视图,从上面看到的图形是俯视图判断即可.
解:几何体的左视图是
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
故选:B

5.C

【解析】
根据矩形的判定,相似三角形的性质,方差的意义,平行公理逐项分析判断即可求解.
解:A. 对角线相等的平行四边形是矩形,故该选项不正确,不符合题意;
B.
相似三角形的面积的比等于相似比的平方,故该选项不正确,不符合题意;
C.
方差越大,数据的波动越大;方差越小,数据的波动越小,故该选项正确,符合题意;
D.
同一平面内,过直线外一点有且只有一条直线与已知直线平行,故该选项不正确,不符合题意;
故选C

6.A

【解析】
由中位数、众数的定义进行计算,即可得到答案.
解:根据题意,
这组数据按从小到大排列为:2628283030303234
这组数据的中位数是第5个数和第6个数的平均数为30;出现最多的数是30,则众数是30
故选:A

7.D

【解析】
根据“上加下减,左加右减”的平移规律即可求解.
解:将函数y=3x +2的图象向下平移3个单位长度,所得的函数的解析式是y=3x﹣1,
故选:D

8.A

【解析】
AB中点G点,根据菱形的性质可知E点、G点关于对角线AC对称,即有PE=PG,则当GPF三点共线时,PE+PF=PG+PF最小,再证明四边形AGFD是平行四边形,即可求得FG=AD
解:取AB中点G点,连接PG,如图,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
四边形ABCD是菱形,且边长为2
AD=DC=AB=BC=2
E点、G点分别为ADAB的中点,
根据菱形的性质可知点E、点G关于对角线AC轴对称,
PE=PG
PE+PF=PG+PF
即可知当GPF三点共线时,PE+PF=PG+PF最小,且为线段FG
如下图,GPF三点共线,连接FG
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
F点是DC中点,G点为AB中点,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
在菱形ABCD中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
四边形AGFD是平行四边形,
FG=AD=2
PE+PF的最小值为2
故选:A

9.C

【解析】
由圆锥的侧面积、圆柱侧面积、圆的面积公式、分别求出答案,再进行判断,即可得到答案.
解:根据题意,
底面圆半径DE=2m
圆柱的底面积为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ;故A正确;
圆柱的侧面积为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ;故B正确;
圆锥的母线为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ;故C错误;
圆锥的侧面积为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ;故D正确;
故选:C

10.C

【解析】
根据二次函数的图象与性质一一判断即可.
解:由图像可知,开口向上,图像与y轴负半轴有交点,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
对称轴为直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,故①正确;
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,故②正确;
对称轴为直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
抛物线与x轴负半轴的交点为( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 0),
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
两式相加,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,故③错误;
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
根据开口向上,离对称轴越近其对应的函数值越小,则有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,故④正确;
正确的结论有3个,
故选:C

11.

【解析】
先分别计算两个数的平方,然后进行比较即可解答.
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 32=9
∴7
9
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 3
故答案为:<.

12.10

【解析】
根据平方差公式,把原式化为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,即可求解.
解:a2b2 +2b+9
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
故答案为:10

13.

【解析】
根据点Pm+1m)在第四象限,可得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,从而得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,即可求解.
解:∵点Pm+1m)在第四象限,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
Q(﹣3m+2)在第二象限.
故答案为:二

14.1113##1311

【解析】
根据平方的非负性,算术平方根的非负性求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的值,进而根据等腰三角形的定义,分类讨论,根据构成三角形的条件取舍即可求解.
解:∵(a﹣32+ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> =0
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 为腰时,周长为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 为腰时,三角形的周长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
故答案为:1113

15. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ## <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

【解析】
根据已知得出直角坐标系,通过代入A点坐标( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 30),求出二次函数解析式,再根据把x=4代入抛物线解析式得出下降高度,即可得出答案.
解:建立平面直角坐标系,设横轴x通过AB,纵轴y通过AB中点O且通过C点,则通过画图可得知O为原点,由题意可得:AO=OB=3米,C坐标为(02),
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
通过以上条件可设顶点式y=ax2+2,把点A点坐标( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 30)代入得,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
抛物线解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
当水面下降,水面宽为8米时,有
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 代入解析式,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
水面下降 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 米;
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

16.2022π

【解析】
根据题意有后一段弧的半径总比前一段弧的半径长 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,又因为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,可知任何一段弧的半径都是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的倍数,根据圆心以ABCD四次一个循环,可得弧 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,再根据弧长公式即可作答.
根据题意有:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
...
以此类推可知,故弧 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
即弧 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的半径为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
即弧 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的长度为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

17.0

【解析】
根据零指数幂、绝对值的意义、特殊角的三角函数值、负整数指数幂,二次根式的加减运算进行计算,即可得到答案.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
=
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
=0

18.x1或者3

【解析】
根据分式的混合运算法则即可进行化简,再根据分式有意义的条件确定x可以选定的值,代入化简后的式子即可求解.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
根据题意有: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
即在0123中,
x=1时,原式=x=1
x=3时,原式=x=3

19.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

【解析】
1)把 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 可求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 从而求出反比例函数解析式;根据勾股定理求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 可得点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 坐标,再运用待定系数法求出一次函数解析式;
2)根据一次函数的图象在反比例函数图象下方可得结论.
(1)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
反比例函数解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 代入得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
解得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
设直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(2)
由图象知,当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 时,kx+b <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
不等式kx+b <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的解集为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

20.BC=AD,∠ABC=∠BADAC=BD;证明见详解

【解析】
构造SAS,利用全等三角形的判定与性质即可求解.
已知:BC=AD,∠ABC=∠BAD
求证:AC=BD
证明:在△ABC和△BAD中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
即命题得证.

21.(1)4015
(2)
见详解
(3)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

【解析】
1)用运动时间为0.9h的人数除以其所占比例即可求出总调查人数,总调查人数减去运动时间为0.9h1.5h1.8h2.1h的人数之和即可的运动时间为1.2h的人数,在该人数除以总调查人数即可求出m的值;
2)根据(1)中的数据补全图形即可;
3)用列表法列举即可求解.
(1)
总调查人数4÷10%=40(人),
运动时间1.2h的人数为:40-(4+15+12+3)=6(人),
即其所占比例为:m%=6÷40=15%
m=15
故答案为:4015
(2)
补全图形如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(3)
列表法列举如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
总的可能情况有12种,刚好抽到两名女生的情况有6种,
即恰好抽到两名女的概率为:6÷12= <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
故所求概率为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

22.(1)A厂运送了250吨,B厂运送270吨;
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> A厂运往甲地90吨,运往乙地160吨;B厂运往甲地150吨,运往乙地120吨;

【解析】
1)设A厂运送x吨,B厂运送y吨,然后列出方程组,解方程组即可得到答案;
2)根据题意,列出wa之间的函数关系式,然后进行整理即可,再结合B厂运往甲地的水泥最多150吨,求出总运费最低的方案.
(1)
解:根据题意,设A厂运送x吨,B厂运送y吨,则
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
A厂运送了250吨,B厂运送270吨;
(2)
解:根据题意,则
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
整理得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
B厂运往甲地的水泥最多150吨,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 时,总运费最低;
此时的方案是:
A厂运往甲地90吨,运往乙地160吨;B厂运往甲地150吨,运往乙地120

23.菜园与果园之间的距离为630

【解析】
过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 是矩形,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 中,求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> CF=240,进而求得AE=210,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 中,利用正切进行求解即可.
解:如图,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
∵∠
B=90°
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 是矩形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> BC=EF
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
BE=240
AE=AB-BE=210
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 米.
BC=EF=DF+DE=180+450=630
答:菜园与果园之间的距离630米.

24.见解析

【解析】
根据轴对称图形的定义、中心对称图形的定义画出图形即可
解:如下图所示:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

25.(1)见详解
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

【解析】
1)连接OD,只要证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,则有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,即可证明结论成立;
2)由圆周角定理,求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,然后证明△ACD∽△DCB,求出CD的长度,再根据勾股定理,即可求出答案.
(1)
证明:连接OD,如图
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
AB为⊙O的直径,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
OA=OD
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
∵∠
BDC=∠BAD
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
CDO的切线.
(2)
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
∵△
ABD是直角三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
∴△
ACD∽△DCB
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
在直角△CDO中,设O的半径为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,则
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
⊙O的半径为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

26.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(2)
-2-4
(3)
P点坐标为:(-13),(-1-5), <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>

【解析】
1)直接将B0-4),C20)代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,即可求出解析式;
2)先求出直线AB关系式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,直线AB平移后的关系式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,当其与抛物线只有一个交点时,此时点DAB最大,此时△ABD的面积最大,由此即可求得D点坐标;
3)分三种情况讨论,①当∠PAB=90°时,即PAAB,则设PA所在直线解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,将A-4,0)代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 得,解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,此时P点坐标为:(-1,3);②当∠PBA=90°时,即PBAB,则设PB所在直线解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,将B0-4)代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,此时P点坐标为:(-1,-5);③当∠APB=90°时,设P点坐标为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> ,由于PA所在直线斜率为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> PB在直线斜率为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> =-1,则此时P点坐标为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(1)
解:将B0-4),C20)代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
抛物线的函数解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
(2)
向下平移直线AB,使平移后的直线与抛物线只有唯一公共点D时,此时点D到直线AB的距离最大,此时△ABD的面积最大,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
A点坐标为:(-4,0),
设直线AB关系式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
A-4,0),B0-4),代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
直线AB关系式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
设直线AB平移后的关系式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
则方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 有两个相等的实数根,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 有两个相等的实数根
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 的解为:x=-2
x=-2代入抛物线解析式得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
D的坐标为:(-2-4)时,△ABD的面积最大;
(3)
当∠PAB=90°时,
PAAB,则设PA所在直线解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
A-4,0)代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
PA所在直线解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
抛物线对称轴为:x=-1
x=-1时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
P点坐标为:(-13);
当∠PBA=90°时,
PBAB,则设PB所在直线解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
B0-4)代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
PA所在直线解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
x=-1时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
P点坐标为:(-1-5);
当∠APB=90°时,设P点坐标为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
PA所在直线斜率为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> PB在直线斜率为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
PAPB
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> =-1
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
P点坐标为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>
综上所述,P点坐标为:(-13),(-1-5), <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1074/" title="四川省" class="c1" target="_blank">四川省</a> <a href="/tags/1108/" title="广安" class="c1" target="_blank">广安</a> <a href="/tags/1004/" title="四川" class="c1" target="_blank">四川</a> 时,△PAB为直角三角形.