1 . 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
2 . 已知非空正实数有限集合A,定义集合
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b65fc3cd4d73993db28934c2584ba44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33da439cbb5d0c47765d0009f80fa969.png)
您最近一年使用:0次
名校
解题方法
3 . 在
中,
,
,
,
分别在线段
和
上,
,
,直线
于
.现将三角形
沿着
对折,当平面
与平面
的二面角为
时,则线段
的长度为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43136f56e59f3f9e878d0c5d4ccbeecd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ffc2817fa590affb5a760a25dc65308.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98823cbc09ca52df1fbcc446eba3e44f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40c2b49d2e533b0e30f467e2660123e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5f215a42c4b7078d8d65923eb9980e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1776d156423ea523de87fbca6c0b6019.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d78fc7fcb2762de28dcef8aa3aa0e49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
您最近一年使用:0次
2021-08-20更新
|
898次组卷
|
2卷引用:2021年全国高中数学联赛浙江赛区预赛试题