名校
解题方法
1 . 已知
.
(1)若
,求
;
(2)若
,
,
都为锐角,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ea9f7848c47a6ac3a1b55fcea429942.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f7e3c674336a90a38408bae2ec4c28f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e5ff741ddf4211f6f20b63220bc8893.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f435efcc7869eec21bdba1ed81dc3f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9435dd49ec2c619d84681c290426e7d4.png)
您最近一年使用:0次
2021-11-11更新
|
690次组卷
|
3卷引用:2021年浙江省温州市摇篮杯高一数学竞赛试题
2 . 四面体,又叫三棱锥,是一种简单多面体.指空间两两不相交且不共线的四个平面在空间割出的封闭多面体.它有
个面、
个点、
条棱、
个二面角.若一个四面体的四个顶点
,
,
,
.则可记为四面体
.对下列特殊的四面体,请选择正确得选项( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f8c4c029e552954bd493b49aeab82d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f8c4c029e552954bd493b49aeab82d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
A.若四面体![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
B.若四面体![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
C.各面均为直接三角形且有至少三条棱长为![]() ![]() |
D.若一个平面与正四面体相交得到一个钝角三角形,则该钝角总小于![]() |
您最近一年使用:0次
3 . 在一次数学考试中,高三(1)班中的
位同学的成绩分别为
,
,
,
,
,
,
,
高三(2)班中的
位同学的成绩分别为
,
,
,
,
,
,
,
,则下列说法正确的有( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3304e23f3b0f9569c4140ca89b6498.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c18ea011a4bce91e9f27c828b05b34eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e58ed6bdddbf22c0e8fa173adec76d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9740bae87cbcfb6d389145d64cfd42ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6f6b87e8a5301b439149a0181737e81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e15e398a06d8ffa9071cf32c3e9e73a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6f6b87e8a5301b439149a0181737e81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b765e032d24c1557ff29cb6f70be0a98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73057b576e2ddc315b90e4292e715c48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3304e23f3b0f9569c4140ca89b6498.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/459cc36d02d31815ba9f2d05e130e0cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfd121f4aeca8a78a320fca1fd1c4d07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cbcf82603580ddba4cfdb4efde85a8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e9ba3f640f57c0cece089dfd19b4970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2be88500e8054f3d9ef97c01a16fb75a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5df3451f880c2a1ba1c1901110bd1d25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2be88500e8054f3d9ef97c01a16fb75a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9740bae87cbcfb6d389145d64cfd42ba.png)
A.高三(1)班![]() ![]() |
B.高三(1)班![]() ![]() |
C.高三(1)班![]() ![]() |
D.高三(1)班![]() ![]() |
您最近一年使用:0次
4 . 小东同学参加一次答题活动,答题规则如下:本次答题共
道题,只有答对前
题,才能接下来答下一道题,答错题目,则答题结束;答对题目,则继续答下一题。若小东答题的准确率与题号成反比,且第一题的答题准确率
,小东至少答对两道题的准确率为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e5db9fa0bc36e2308bd3eecd5e78351.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次