名校
解题方法
1 . 如图,在直角梯形
中,
,
,
,
,
分别是
,
的中点,将三角形
沿
折起.下列说法正确的是______ .(填序号)
![](https://img.xkw.com/dksih/QBM/2021/1/27/2645297622016000/2647838462074880/STEM/8b291362-2aba-470e-8ce7-f41f8f63a9b6.png)
①不论
折至何位置(不在平面
内)都有
平面
;
②不论
折至何位置(不在平面
内)都有
;
③在折起过程中,一定存在某个位置,使
平面
;
④当二面角
的大小为
时,四棱锥
的体积取最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/479bb5e937f4fdb1fcbca229e62e0e80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c05986ad5fa244bc1aedf7b5d216544.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://img.xkw.com/dksih/QBM/2021/1/27/2645297622016000/2647838462074880/STEM/8b291362-2aba-470e-8ce7-f41f8f63a9b6.png)
①不论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcf19a7f0dd0cdf59516ae585025110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/678b28fddb166d90878d24d6e5481080.png)
②不论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13c4a875c62b36bcc95d629b780d8ed4.png)
③在折起过程中,一定存在某个位置,使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93cf663ee2bf1ac5c43f4306fa0cf250.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01ff27eea7545bb06f9472f91290c54e.png)
④当二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03a08e6ea74ee085ed9dd4a05af94c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/675127116b1cace5e3158a88b7a2044a.png)
您最近一年使用:0次
2021-01-31更新
|
252次组卷
|
2卷引用:广西北海市2020-2021学年高一上学期期末教学质量检测数学试题