初三第一学期期末学业水平调研
数学试卷答案及评分参考
2019.01
一、选择题(本题共16分,每小题2分)
二、填空题(本题共16分,每小题2分)
9.word/media/image1.gif,word/media/image2.gif 10.word/media/image3.gif
11.2 12.word/media/image4.gif
13.word/media/image5.gif 14.答案不唯一,如:word/media/image6.gif
15.word/media/image7.gif 16.word/media/image8.gif
三、解答题(本题共68分,第17~22题,每小题5分;第23~26题,每小题6分;第27~28题,每小题7分)解答应写出文字说明、验算步骤或证明过程.
17.(本小题满分5分)
解:原式=word/media/image9.gif
=word/media/image10.gif.
18.(本小题满分5分)
证明:∵word/media/image11.gif,word/media/image12.gif,
∴word/media/image13.gif.
∴word/media/image14.gif.
∵word/media/image15.gif,
∴word/media/image16.gif.
19.(本小题满分5分)
解:依题意,得word/media/image17.gif.
∴word/media/image18.gif.
∵word/media/image19.gif,
∴word/media/image20.gif.
∴word/media/image21.gif.
20.(本小题满分5分)
解:(1)B.
(2)word/media/image22.gif.
21.(本小题满分5分)
(1)补全的图形如图所示:
word/media/image23_1.png
(2)直径所对的圆周角是直角;
经过半径的外端并且垂直于这条半径的直线是圆的切线.
22.(本小题满分5分)
解:在word/media/image24.gif中,
∵word/media/image25.gif,
∴word/media/image26.gif.
在word/media/image27.gif中,
∵word/media/image28.gif,
∴word/media/image29.gif.
∴word/media/image30.gif.
∵word/media/image31.gif,word/media/image32.gif°,word/media/image33.gif°,
∴word/media/image34.gif.
答:此时观光船到大桥word/media/image35.gif段的距离word/media/image36.gif的长为word/media/image37.gif千米.
23.(本小题满分6分)
解:(1)∵直线word/media/image38.gif经过点word/media/image39.gif,
∴word/media/image40.gif.
∴word/media/image41.gif
又∵双曲线word/media/image42.gif经过点word/media/image43.gif,
∴word/media/image44.gif.
(2)①当word/media/image21.gif时,点word/media/image45.gif的坐标为word/media/image5.gif.
∴直线word/media/image46.gif的解析式为word/media/image47.gif.
∵直线word/media/image48.gif与word/media/image49.gif轴交于点word/media/image50.gif,
∴word/media/image51.gif.
②word/media/image52.gif或word/media/image53.gif.
24.(本小题满分6分)
解:本题答案不唯一,如:
(1)
(2)
word/media/image56_1.png
(3)word/media/image57.gif或word/media/image58.gif.
说明:允许(1)的数值误差范围word/media/image59.gif;(3)的数值误差范围word/media/image60.gif
25.(本小题满分6分)word/media/image61_1.png
(1)证明:如图,连接word/media/image62.gif.
∵word/media/image63.gif,
∴word/media/image64.gif°
∵word/media/image65.gif与⊙word/media/image66.gif相切于点word/media/image67.gif,
∴word/media/image68.gif°.
∴word/media/image69.gif°.
∵word/media/image70.gif,
∴word/media/image71.gif.
∴word/media/image72.gif.
又∵word/media/image73.gif,
∴word/media/image74.gif.
∴word/media/image75.gif.
(2)方法一:
解:如图,过点word/media/image76.gif作word/media/image77.gif于点word/media/image78.gif.
∵word/media/image79.gif,word/media/image80.gif,
∴word/media/image82.gif.word/media/image81_1.png
∵word/media/image83.gif,
∴word/media/image84.gif°.
∴word/media/image85.gif°.
在word/media/image86.gif中,word/media/image87.gif,
可得word/media/image88.gif°word/media/image89.gif,word/media/image90.gif°word/media/image89.gif.
在word/media/image91.gif中,word/media/image92.gif,
可得word/media/image93.gif.
∴word/media/image94.gif.
∴word/media/image95.gif.
∴word/media/image96.gif.
∴word/media/image97.gif.
方法二:word/media/image98_1.png
解:如图,过点word/media/image67.gif作word/media/image99.gif于点word/media/image78.gif.
∵word/media/image79.gif,word/media/image80.gif,
∴word/media/image100.gif°.
∵word/media/image83.gif,
∴word/media/image84.gif°.
在word/media/image101.gif中,word/media/image87.gif,
可得word/media/image102.gif°word/media/image89.gif.
∴word/media/image103.gif.
∵word/media/image104.gif,word/media/image92.gif,
∴word/media/image105.gif.
在word/media/image106.gif中,word/media/image107.gif,word/media/image108.gif.
∴word/media/image109.gif,word/media/image110.gif.
∴word/media/image111.gif.
在word/media/image112.gif中,word/media/image113.gif,word/media/image114.gif.
设word/media/image115.gif,则word/media/image116.gif,word/media/image117.gif.
∵word/media/image75.gif,
∴word/media/image118.gif.
∵word/media/image119.gif,word/media/image120.gif,
∴word/media/image121.gif∽word/media/image122.gif
∴word/media/image123.gif.
∴word/media/image124.gif.
∴word/media/image125.gif.
方法三:
解:如图,过点word/media/image67.gif作word/media/image126.gif于点word/media/image78.gif,连接word/media/image35.gif.
∵word/media/image79.gif,word/media/image80.gif,
∴word/media/image82.gif.
∴word/media/image128.gif°.word/media/image127_1.png
在word/media/image112.gif中,word/media/image129.gif,
设word/media/image115.gif,则word/media/image116.gif,word/media/image130.gif.
在word/media/image131.gif中,word/media/image132.gif°,word/media/image115.gif,
∴word/media/image133.gif,word/media/image134.gif.
∴word/media/image135.gif.
∵word/media/image136.gif,word/media/image137.gif,
∴word/media/image138.gif.
∴word/media/image139.gif.
∵word/media/image87.gif,
∴word/media/image140.gif,word/media/image141.gif,word/media/image142.gif.
∵word/media/image143.gif,
∴word/media/image144.gif.
∴word/media/image145.gif.
方法四:
解:如图,延长CO交AP于点M.
∵word/media/image146.gif,word/media/image147.gif,
∴word/media/image149.gif.
在word/media/image150.gif中,word/media/image151.gif,word/media/image152.gif,
可得word/media/image153.gif.
∵word/media/image154.gif,word/media/image92.gif,
∴word/media/image155.gif.
在word/media/image156.gif中,word/media/image157.gif,
可得word/media/image158.gif,word/media/image159.gif.
∴word/media/image160.gif.
在word/media/image161.gif中,word/media/image162.gif,
可得word/media/image163.gif,word/media/image164.gif.
∴word/media/image165.gif,word/media/image166.gif.
∴word/media/image145.gif.
26.(本小题满分6分)word/media/image167_1.png
解:(1)①当word/media/image40.gif时,word/media/image168.gif.
当word/media/image169.gif时,word/media/image170.gif,
解得word/media/image1.gif,word/media/image171.gif.
∴抛物线word/media/image172.gif与word/media/image173.gif轴的交点坐标为word/media/image174.gif,word/media/image175.gif.
②当word/media/image176.gif时,抛物线word/media/image172.gif与线段word/media/image177.gif有一个交点.
当word/media/image178.gif时,抛物线word/media/image172.gif与线段word/media/image177.gif有两个交点.
结合图象可得word/media/image179.gif.
(2)word/media/image180.gif或word/media/image181.gif.
27.(本小题满分7分)word/media/image182.gif
(1)①证明:连接word/media/image183.gif,如图1.
∵点word/media/image67.gif与点word/media/image184.gif关于直线word/media/image185.gif对称,
∴word/media/image186.gif.
∵word/media/image187.gif,
∴word/media/image188.gif.
∴点word/media/image189.gif在以word/media/image43.gif为圆心,word/media/image190.gif为半径的圆上.
②word/media/image192.gif.word/media/image191.gif
(2)证法一:
证明:连接word/media/image193.gif,如图2.
∵word/media/image194.gif°,
∴word/media/image195.gif°.
∵word/media/image196.gif,
∴word/media/image197.gif°word/media/image198.gif°.
∵点word/media/image67.gif与点word/media/image184.gif关于直线word/media/image185.gif对称,
∴word/media/image199.gif.
∴word/media/image200.gif是等边三角形.
∴word/media/image201.gif,word/media/image202.gif°.
∵word/media/image187.gif,word/media/image203.gif°,
∴word/media/image204.gif是等边三角形.
∴word/media/image205.gif,word/media/image206.gif°.
∵word/media/image207.gif,word/media/image208.gif,
∴word/media/image209.gif.
∴word/media/image210.gif.
∴word/media/image211.gif.
证法二:word/media/image212.gif
证明:连接word/media/image213.gif,如图2.
∵点word/media/image67.gif与点word/media/image184.gif关于直线word/media/image185.gif对称,
∴word/media/image214.gif.
∴word/media/image215.gif.
∵word/media/image216.gif,
∴word/media/image217.gif.
∵word/media/image218.gif,word/media/image219.gif,
∴word/media/image220.gif°.
∴word/media/image221.gif.
∵word/media/image222.gif°,
∴word/media/image204.gif是等边三角形,
∴word/media/image223.gif.
∴word/media/image224.gif≌word/media/image225.gif
∴word/media/image211.gif.
(3)word/media/image226.gif.
28.(本小题满分7分)
解:(1)图1中点word/media/image67.gif的坐标为word/media/image227.gif.
(2)改变图1中的点word/media/image43.gif的位置,其余条件不变,则点word/media/image67.gif的纵坐标不变,
它的值为3.
(3)①判断:结论“点word/media/image67.gif落在word/media/image173.gif轴上,则点word/media/image184.gif落在第一象限内.”错误.
反例如图所示:
word/media/image228_1.png
②word/media/image229.gif.
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