在如图所示的四棱锥
中,四边形
是等腰梯形,
,
,
平面
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/a24af61c-7ae8-4188-997d-dce7734cc9ac.png?resizew=151)
(1)求二面角
的余弦值.
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e5ba482836565abad208665cf7b9972.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7b5a90e556da12d63b7f481bd8e874c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/111e8adcc9c7840748f246a8823d6e25.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/a24af61c-7ae8-4188-997d-dce7734cc9ac.png?resizew=151)
(1)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e9d40f58f5fd5fb401a529a42b93ff1.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/138a5261a4cd0cb1f14b1dfccd4d916d.png)
更新时间:2021-10-21 12:08:12
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【推荐2】已知正四棱柱ABCD-A1B1C1D1的底面边长为3,A1D=5.
(1)求三棱柱A1-BCD的体积;
(2)若E为线段A1D的中点,求BE与平面ABCD所成角的大小.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/4/a08a9b91-e567-410c-8b31-edfdc5e27adf.png?resizew=132)
(1)求三棱柱A1-BCD的体积;
(2)若E为线段A1D的中点,求BE与平面ABCD所成角的大小.
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【推荐3】如图,在四棱锥
中,底面
为正方形,
平面
,M为PC中点.
平面
;
(2)若
,求直线
与平面
所成角的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/373f735f0f04d11f1951eaef1bb78b6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9af29254fe60a392c249c5791279e9c8.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96127e45e2dd2494fccb1c0905951f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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【推荐1】如图,四棱锥
的底面
为一直角梯形,其中
,
底面
,
是
的中点.
![](https://img.xkw.com/dksih/QBM/2010/4/24/1569703326613504/1569703332020224/STEM/0e9f634867974791bf964316a5a8a9e3.png?resizew=220)
(1)求证:
//平面
;
(2)若
平面
,
①求异面直线
与
所成角的余弦值;
②求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09924b97c96c50472b7f6f4fdeed1b0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f560e74654e9aae08b03d2dad56abf1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/2010/4/24/1569703326613504/1569703332020224/STEM/0e9f634867974791bf964316a5a8a9e3.png?resizew=220)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/662698361c6b3ddaf0c28a3c87be53e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
①求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
②求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d682fd0344452998187cb6d48de3dd1.png)
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【推荐2】图1是由矩形
,
和菱形
组成的一个平面图形,其中
,
,
.将该图形沿
,
折起使得
与
重合,连接
,如图2.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/16/405a154a-5a71-41f3-85b6-164b4432508d.png?resizew=278)
(1)证明:图2中C,D,E,G四点共面;
(2)求图2中二面角
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ddcd5435b39971f897210aa0b66a259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40e7ba6e267dde1a65a98f9f36b585ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6eaeff3c3502abbcf1626bac6a9de96.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/16/405a154a-5a71-41f3-85b6-164b4432508d.png?resizew=278)
(1)证明:图2中C,D,E,G四点共面;
(2)求图2中二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a17158a669a634e3db538ce76471950.png)
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