1 . 如图所示,在平行四边形
中,
,
,
,将△
沿
折起到△
的位置,使平面
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/19/3229f0c6-84bd-488c-8ebb-61de02aaa90f.png?resizew=149)
(Ⅰ)求证:
;
(Ⅱ)若点
为
的中点,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea4f5eec0addba78f2e0cdfb7ecc59a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc11331a7b2d2619b40ee6d34c3bd620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9dfaad4c4467e27421876d8f2a4371d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65277734669566578cbb7d690bb200fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e54cf75bbfc9db93d27937c8b8e977b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abd284f76d9f5769bc189508ce2572b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/19/3229f0c6-84bd-488c-8ebb-61de02aaa90f.png?resizew=149)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9874eca4abea481fa84eb772a920f9c7.png)
(Ⅱ)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
您最近一年使用:0次
2021-09-11更新
|
334次组卷
|
3卷引用:广东省高州市第七中学等三校2022-2023学年高二上学期11月月考数学试题
2 . 已知在三棱锥
中,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/17/078c5af6-d62c-43a2-bccf-bf5a7015ca9c.png?resizew=138)
(1)求证:
;
(2)若
,
,求二面角
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba1af71094b0522a0df6c7fae1580e48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90dbe55407b556be48d67cde5c5dc94f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/17/078c5af6-d62c-43a2-bccf-bf5a7015ca9c.png?resizew=138)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a15a004f7d47ed595f063e60075223a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96127e45e2dd2494fccb1c0905951f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91f0f9487303d04e6914b29ae805a0f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12a4bddf1ea3c5d37f2233a4821909e9.png)
您最近一年使用:0次