0  204240  204248  204254  204258  204264  204266  204270  204276  204278  204284  204290  204294  204296  204300  204306  204308  204314  204318  204320  204324  204326  204330  204332  204334  204335  204336  204338  204339  204340  204342  204344  204348  204350  204354  204356  204360  204366  204368  204374  204378  204380  204384  204390  204396  204398  204404  204408  204410  204416  204420  204426  204434  447090 

23.解:(1)该商场销售家电的总收益为(元)·························· 2分

(2)依题意可设

解得

所以.··········································································· 3分

(3)

政府应将每台补贴款额定为100元,总收益有最大值.

其最大值为元.································································································ 3分

试题详情

22.解:(1)设一次购物用6个袋的人数为人,则依条件有

,则记者共调查了人.··················· 2分

(2)这100位顾客平均一次购物使用购物袋的平均数为

(个)

个.

估计这三大商业集团为顾客每天提供18000个塑料购物袋.·········································· 3分

(3)74%;25;

多数人环保意识增强,(只要是涉及环保节能等方面思想向上的即可).····················· 3分

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21.解:在中,

.······················ 3分

中,

.········································································ 3分

.························································································· 2分

答:发射架高为25m.

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20.解:(1)当时,函数为,它的图象显然与

只有一个交点.·································································································· 2分

时,依题意得方程有两等实数根.

时函数图象与轴恰有一个交点.··················································· 2分

(2)依题意有分类讨论解得

时,抛物线顶点始终在轴上方.······················································· 4分

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19.解:原式·························································· 4分

.···································································································· 2分

时,原式.························································································ 1分

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18.证明:

.····················································· 2分

,即.························ 2分

.·············································································································· 3分

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17.解:原式··········································································· 4分

       ········································································································ 3分

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11.   12.60°   13.3∶5    14.   15.   16.

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25.(本小题满分10分)

正方形在如图所示的平面直角坐标系中,轴正半轴上,轴的负半轴上,轴正半轴于轴负半轴于,抛物线三点.

(1)求抛物线的解析式;(3分)

(2)是抛物线上间的一点,过点作平行于轴的直线交边,交所在直线于,若,则判断四边形的形状;(3分)

(3)在射线上是否存在动点,在射线上是否存在动点,使得,若存在,请给予严格证明,若不存在,请说明理由.(4分)

 

黄石市2009年初中毕业生学业考试

数学答案及评分标准

试题详情

24.(本小题满分9分)

如图,中,点是边上一个动点,过作直线,设的平分线于点,交的外角平分线于点

(1)探究:线段的数量关系并加以证明;(3分)

(2)当点在边上运动时,四边形会是菱形吗?若是,请证明,若不是,则说明理由;(3分)

(3)当点运动到何处,且满足什么条件时,四边形是正方形?(3分)

 

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