如图,四棱锥
的底面为矩形,
底面
,设平面
与平面
的交线为m.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/13/9a6cc04d-e30c-4f87-904b-c268d0c080ef.png?resizew=142)
(1)证明:
,且
平面
;
(2)已知
,R为m上的点求
与平面
所成角的余弦值的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fb2e071d4e01107dcf7d95cbb86b415.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d923a338dd2d2e29336b42574d38448.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21665d21bbfb04410c78345de1fd15ae.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/13/9a6cc04d-e30c-4f87-904b-c268d0c080ef.png?resizew=142)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bcd6b9e470aab93e77dab8ce476eb85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f979a27d3a09a17445561091e6655eb6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5da631296d53a08d56fb5f9bec2376c.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/517d67c30a82da664d5663a401ced466.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d4db9b82b67efe45a02fca32bfcf5dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9511bd2adf8e8614c7bba2a1580c7044.png)
更新时间:2021-09-12 00:25:23
|
【知识点】 线面角的向量求法
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解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,四棱锥P﹣ABCD中,底面ABCD为梯形,AB∥DC,∠BAD=90°,点E为PB的中点,且CD=2AD=2AB=4,点F在CD上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/12/25c66b62-d8a5-43ec-a276-379a78770173.png?resizew=171)
(Ⅰ)求证:EF∥平面PAD;
(Ⅱ)若平面PAD⊥平面ABCD,PA=PD且PA⊥PD,求直线PA与平面PBF所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a986e6cfd114c3c7978be62259e7c19d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/12/25c66b62-d8a5-43ec-a276-379a78770173.png?resizew=171)
(Ⅰ)求证:EF∥平面PAD;
(Ⅱ)若平面PAD⊥平面ABCD,PA=PD且PA⊥PD,求直线PA与平面PBF所成角的正弦值.
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解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图,
是一个三棱锥,
是圆的直径,
是圆上的一点,
垂直于圆所在的平面,
分别是棱
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/37b45eb6-220d-4bf8-9dda-62cad384bcee.png?resizew=159)
(1)求证:
平面
;
(2)若二面角
是
,
,求
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3a51949f48ee8cf746851ba779b078e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ace5e8c3769ad8f370c86f879246c174.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/37b45eb6-220d-4bf8-9dda-62cad384bcee.png?resizew=159)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d2d217e9bcd059908f117dfc4d4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51e231505648333857565accb0c3c898.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1e5fa72f2878b476bc57f0df12d6555.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3304d151a8d42f932fbfb96f06bd9b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
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