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【327984】广西贵港市2021年中考数学真题

时间:2025-01-20 20:55:14 作者: 字数:18660字
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绝密·启用前

广西贵港市2021年中考数学真题

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/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

2.若分式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 在实数范围内有意义,则x的取是(
A
x≠5
B
x≠0
C
x≠5
D
x>-5

3.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/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
B
2aa1
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

4.一组数据878649的中位数和平均数分别是( )
A
78
B
7.57
C
77
D
77.5

5.在平面直角坐标系中,若点P(a31)与点Q(2b1)关于x轴对称,ab是(
A
1
B
2
C
3
D
4

6.不等式12x3x1的解集是(
A
1x2
B
2x3
C
2x4
D
4x5

7.已知关于x的一元二次方程x2kxk30的两个数根分别为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> k是(
A
.-2
B
2
C
.-1
D
1

8.下列命题是真命题的是( )
A
.同旁内角相等,两直线平行
B
.对角线相等的四边形是矩形
C
.对角线互相垂直的四边形是菱形
D
.两角分别相等的两个三角形相似

9.某蔬菜种植基地2018年的蔬菜产量为800吨,2020年的蔬菜产量为968吨,设每年蔬菜产量的年平均增长率都为x年平均增x应满足的方程
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

10.如图,点ABCD均在O上,直径AB4,点C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的中点,点D关于AB称的点E,若DCE100°CE是(
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
B
2
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
D
1

11.如图,在正方形ABCD中,EF线AC上的两点,且EF2AE2CFDE并延AB于点MDF并延BC于点NMN <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
C
1
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

12.如图,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ABC中,ABC90°AB8BC12DAC上的一个点,BDEBD上的一个点,AECE,当ABDBCE线AE的最小是(
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
A
3
B
4
C
5
D
6

评卷人

得分




二、填空题

13.甲、乙两人在相同条件下进行射击练习,每人10次射击战绩的平均数都是8环,方差分别为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,则两人射击成绩比较稳定的是________(填“甲”或“乙”).

14.第七次全国人口普查公布的我国总人口数约为1411780000人,将数据1411780000用科学记数法表示为________

15.如图,ABCDCB平分ECD,若B26°1的度数是________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

16.如图,圆锥的高是4,它的侧面展开图是圆心角为120°的扇形,则圆锥的侧面积是________.(结果保留 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

17.如图,在矩形ABCD中,BD线AEBD,垂足ECE,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> tanDEC________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

18.我们规定:若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> .例如 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> .已知 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的最大值是________

评卷人

得分




三、解答题

19.1)计算: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
2)解分式方程: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

20.尺规作图(只保留作图痕迹,不要求写出作法),如图,已知 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ABC,且ABAC
1)在AB上求作点D,使DBDC
2)在AC上求作点E,使 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ADE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ACB
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

21.如图,一次函数yx2象与反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 象相交,其中一个交点的横坐1
1)求k
2)若将一次函数yx2象向下平移4度,平移后所得到的象与反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 象相交于AB两点,求此时线AB
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

22.某校为了了解本校学生每天课后进行体育锻炼的时间情况,在5月份某天随机抽取了若干名学生进行调查,调查发现学生每天课后进行体育锻炼的时间都不超过100分钟,现将调查结果绘制成如下两幅尚不完整的统计图表.请根统计图表提供的信息,解答下列问题:


组别


锻炼时间(分)


频数(人)


百分比


A


0≤
x≤20


12


20%


B


20
x≤40


a


35%


C


40
x≤60


18


b


D


60
x≤80


6


10%


E


80
x≤100


3


5%


 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
1)本次调查的样本容量是 ;表中a b
2)将数直方图补充完整;
3)已知E2名男生和1名女生,从中随机抽取两名学生,恰好抽到1名男生和1名女生的概率是
4)若校学生共有2200人,根据以上调查结果估校每天行体育锻炼时间60的学生共有多少人?

23.某公司需将一批材料运往工厂,计划租用甲、乙两种型号的货车,在每辆货车都满载的情况下,若租用30辆甲型货车和50辆乙型货车可装1500箱材料;若租用20辆甲型货车和60辆乙型货车可装载1400箱材料.
1)甲、乙两种型号的货车每辆分别可装载多少箱材料?
2)经初步估算,公司要运往工厂的这批材料不超过1245箱,计划租用甲、乙两种型号的货车共70辆,且乙型货车的数量不超过甲型货车数量的3倍,该公司一次性将这批材料运往工厂共有哪几种租车方案?

24.如图,⊙O <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ABC的外接ADO的直径,FAD长线上一点,CDCF,且DCFCAD
1)求CFO的切线
2)若cosB <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> AD2,求FD
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

25.如图,已知抛物线yax2bxcx相交于A(30)B两点,与y相交于点C(02)是直线x=-1AC
1)求抛物线的表达式;
2)若B的直线l与抛物线相交于另一点D,当ABDBAC,求直线l的表达式;
3)在(2)的条件下,当点Dx下方AD,此y的抛物线上存在点P,使 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 直接写出所有符合条件的点P的坐
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

26.已知在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ABC中,OBC的中点,AO,将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> AOCO顺时针方向旋(旋为钝角),得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> EOFAECF
1)如1,当BAC90°ABACAECF足的数量关系是
2)如2,当BAC90°AB≠AC,(1)中的结论是否仍然成立?若成立,写出程;若不成立,请说明理由;
3)如3,延AO到点D,使ODOADE,当AOCF5BC6,求DE
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

参考答案

1.B

【解析】
根据负数的绝对值是它的相反数,可得出答案.
根据绝对值的性质得:|-3|=3
故选B

2.A

【解析】
根据分式有意义的条件列不等式求解.
解:根据分式有意义的条件,可得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故选:A

3.C

【解析】
根据合并同类项的运算法则、单项式乘单项式和幂的乘方的运算法则解答即可.
解:A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,原计算错误,故此选项不符合题意;
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,原计算错误,故此选项不符合题意;
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,原计算正确,故此选项符合题意;
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,原计算错误,故此选项不符合题意.
故选:C

4.B

【解析】
根据中位数、平均数的定义分别列出算式,再进行计算即可.
解:把这些数从小到大排列为467889
则中位数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
平均数是: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故选:B

5.C

【解析】
直接利用关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴对称点的性质:横坐标不变,纵坐标互为相反数,即可得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的值,进而得出答案.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 与点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴对称,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故选:C

6.C

【解析】
分别求出各不等式的解集,再求出其公共部分即可.
解:不等式组化为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
由不等式①,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
由不等式②,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故原不等式组的解集是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故选:C

7.D

【解析】
利用根与系数的关系得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,进而得出关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的一元二次方程求出即可.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的一元二次方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的两个实数根分别为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
整理得出: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故选:D

8.D

【解析】
利用平行线的判定方法、矩形及菱形的判定方法、相似三角形的判定方法分别判断后即可确定正确的选项.
解:A、同旁内角互补,两直线平行,故原命题错误,是假命题,不符合题意;
B
、对角线相等的平行四边形是矩形,故原命题错误,是假命题,不符合题意;
C
、对角线互相垂直的平行四边形是菱形,故原命题错误,是假命题,不符合题意;
D
、两角分别相等的两个三角形相似,正确,是真命题,符合题意,
故选:D

9.B

【解析】
根据该种植基地2018年及2020年的蔬菜产量,即可得出关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的一元二次方程,此题得解.
解:依题意得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故选:B

10.A

【解析】
连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,根据圆内接四边形的性质得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,根据对称以及圆周角定理可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,由点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的中点可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,根据等腰三角形以及直角三角形的性质即可求解.
解:连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 对称的点为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的中点,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 直径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故选:A

11.A

【解析】
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,首先证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,再利用平行线分线段成比例定理求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,推出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,可得结论.
解:设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 是正方形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故选:A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

12.B

【解析】
如图,取 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的中点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> .首先证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,可得结论.
解:如图,取 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的中点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的最小值为4
故选:B

13.

【解析】
根据方差的意义即方差越小,表明这组数据分布比较集中,各数据偏离平均数越小,数据越稳定,即可得出答案.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 两人射击成绩比较稳定的是乙.
故答案为:乙.

14. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
科学记数法的表示形式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的形式,其中 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 为整数.确定 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的值时,要看把原数变成 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 时,小数点移动了多少位, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的绝对值与小数点移动的位数相同.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故答案是: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

15. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
根据平行线的性质得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,根据角平分线定义求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,再根据平行线的性质即可得解.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 平分 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

16. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
设圆锥的底面半径为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,母线长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,根据题意得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,然后根据高为4,利用勾股定理得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,从而求得底面半径和母线长,利用侧面积公式求得答案即可.
解:设圆锥的底面半径为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,母线长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
根据题意得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 高为4
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 母线长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 圆锥的侧面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

17. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,易证 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,从而可求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,设ABa,则AD2a,根据三角形的面积可求出AE然后根据角三角函数的定即可求出答案.
解:如 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> tanADB <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
ABa,则AD2a
BD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> a
SABD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> BDAE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ABAD
AECF <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> a
BEFD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> a
EFBD2BE <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> a <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> a <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> a
tanDEC <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

18.8

【解析】
根据平面向量的新定义运算法则,列出关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的二次函数,根据二次函数最值的求法解答即可.
解:根据题意知: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
因为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
所以当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的最大值是8
故答案是:8

19.1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ;(2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
1)先分别化简二次根式,零指数幂,有理数的乘方,特殊角三角函数值,然后再计算;
2)将分式方程转化为整式方程,然后解方程,注意分式方程的结果要进行检验.
解:(1)原式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
2)整理,得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
方程两边同时乘以 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
检验:当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 是原分式方程的解.

20.1)见解析;(2)见解析

【解析】
1)作线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的垂直平分线交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 即可.
2)作 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,射线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 即为所求.
解:(1)如图,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 即为所求.
2)如图,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 即为所求.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

21.13;(2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
1)将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,故其中交点的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 代入反比例函数表达式,即可求解;
2)一次函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的图象向下平移4个单位得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,一次函数和反比例函数解析式联立,解方程组求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的坐标,然后根据勾股定理即可求解.
解:(1)将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 交点的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
2)将一次函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的图象向下平移4个单位长度得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

22.1602130%;(2)见解析;(3 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ;(4330

【解析】
1)由 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的人数除以所占百分比求出样本容量,即可解决问题;
2)将频数分布直方图补充完整即可;
3)画树状图,共有6种等可能的结果,恰好抽到1名男生和1名女生的结果有4种,再由概率公式求解即可;
4)由该校学生总人数乘以每天课后进行体育锻炼的时间超过60分钟的学生所占的百分比即可.
解:(1)本次调查的样本容量是: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故答案为:6021 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
2)将频数分布直方图补充完整如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
3)画树状图如图:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
共有6种等可能的结果,恰好抽到1名男生和1名女生的结果有4种,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 恰好抽到1名男生和1名女生的概率为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
4 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> (人),
即该校每天课后进行体育锻炼的时间超过60分钟的学生共有330人.

23.1)甲型货车每辆可装载25箱材料,乙型货车每辆可装载15箱材料;(2)见解析

【解析】
1)设甲型货车每辆可装载 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 箱材料,乙型货车每辆可装载 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 箱材料,根据“若租用30辆甲型货车和50辆乙型货车可装载1500箱材料;若租用20辆甲型货车和60辆乙型货车可装载1400箱材料”,即可得出关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的二元一次方程组,解之即可得出结论;
2)设租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 辆甲型货车,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 辆乙型货车,根据“租用的乙型货车的数量不超过甲型货车数量的3倍,且要运往工厂的这批材料不超过1245箱”,即可得出关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的一元一次不等式组,解之即可得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的取值范围,结合 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 为整数,即可得出各租车方案.
解:(1)设甲型货车每辆可装载 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 箱材料,乙型货车每辆可装载 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 箱材料,
依题意得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
答:甲型货车每辆可装载25箱材料,乙型货车每辆可装载15箱材料.
2)设租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 辆甲型货车,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 辆乙型货车,
依题意得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 为整数,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 可以取1819
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 该公司共有2种租车方案,
方案1:租用18辆甲型货车,52辆乙型货车;
方案2:租用19辆甲型货车,51辆乙型货车.

24.1)见解析;(2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
1)根据切线的判定,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,证明出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 即可,利用直径所得的圆周角为直角,三角形的内角和以及等腰三角形的性质可得答案;
2)由 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,根据锐角三角函数的意义和勾股定理可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,再根据相似三角形的性质可求出答案.
解:(1)连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的直径,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的切线;
2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> (取正值),
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

25.1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ;(2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ;(3 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
1)先根据对称轴得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,再由点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的坐标求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,最后将点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的坐标代入抛物线解析式求解,即可得出结论;
2)分两种情况,Ⅰ、当点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴上方时,先判断出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,进而得出点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 在直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 上,再求出点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的坐标,最后用待定系数法求出直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式;Ⅱ、当点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴下方时,判断出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,即可得出结论;
3)先求出点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的坐标,进而求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的面积,得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的面积,设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,过 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴的平行线交直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,进而表示出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,最后用面积建立方程求解,即可得出结论.
解:(1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 抛物线的对称轴为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 抛物线的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 在抛物线上,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 抛物线的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
2)Ⅰ、当点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴上方时,如图1
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的交点为点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 垂直平分 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 在直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 上,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 对称,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
即直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
、当点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴下方时,如图2
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
由Ⅰ知,直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
即直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
综上,直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
3)由(2)知,直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ①,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 抛物线的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ②,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴左侧的抛物线上,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 轴的平行线交直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> (舍)或 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

26.1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ;(2)成立,证明见解析;(3 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>

【解析】
1)结论 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> .证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,可得结论.
2)结论成立.证明方法类似(1).
3)首先证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,再利用相似三角形的性质求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> ,利用勾股定理求出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a> 即可.
解:(1)结论: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
理由:如图1中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
2)结论成立.
理由:如图2中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
3)如图3中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
由旋转的性质可知 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/1014/" title="广西" class="c1" target="_blank">广西</a> <a href="/tags/1016/" title="贵港" class="c1" target="_blank">贵港</a>