如图,已知菱形
和菱形
的边长均为2,
,
,
分别为
、
上的动点,且
.
平面
;
(2)当
的长最小时,求平面
与平面
的夹角余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ecc1cb55a57dde481f8dd07ab150676.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b31285c747ac70d3ea0beac9b658d027.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/793e03b60fc5ac445d6d44c508e7e73e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6670479a0083dd2dfd5ad55b47b1ab6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b138770c405307ea4fc828624645e2c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcf19a7f0dd0cdf59516ae585025110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6541c0cb89f08aa4c937c0beb915e0a7.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82cb18c10820d927ecd53326f58aaf8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/881129039cb98be128af55ffa1d3b7dc.png)
更新时间:2024-06-04 23:43:46
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图所示,四边形EFGH为空间四边形ABCD的一个截面,若截面为平行四边形.
(1)求证:AB∥平面EFGH,CD∥平面EFGH;
(2)若AB=4,CD=6,求四边形EFGH周长的取值范围.
(1)求证:AB∥平面EFGH,CD∥平面EFGH;
(2)若AB=4,CD=6,求四边形EFGH周长的取值范围.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/17/6468f943-a223-4913-8934-6249eb6e0d12.png?resizew=160)
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【推荐2】如图,四棱锥P-ABCD中,底面ABCD为菱形,PA⊥平面ABCD,E为PD中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/17/06f1be0b-e975-4412-8854-815701b0ec1a.png?resizew=161)
(1)PB∥平面AEC;
(2)设PA=1,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
,三棱锥E-ACD的体积为
,求二面角D-AE-C的余弦值.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/17/06f1be0b-e975-4412-8854-815701b0ec1a.png?resizew=161)
(1)PB∥平面AEC;
(2)设PA=1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b33794d33cbf4dd869a987d110627250.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69a8b76e36783a69d14ec54af82c7df0.png)
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解答题-证明题
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【推荐1】如图,在四棱锥
中,
,
底面
,
是边长为2的菱形,
,正
所在平面与底面
垂直.
![](https://img.xkw.com/dksih/QBM/2022/4/8/2953847934976000/2954472989581312/STEM/c253a32d-6fb2-4092-b310-2028a71673b6.png?resizew=191)
(1)求证:
平面
;
(2)求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9641d01140939c44450bf39773272af6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5f1897a7e856b42f8cee0f286ad913d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d41984f53bb280ba8b5ac00a52ce2825.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/2022/4/8/2953847934976000/2954472989581312/STEM/c253a32d-6fb2-4092-b310-2028a71673b6.png?resizew=191)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72221ee5b504d596ff799c0b356aa0ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e866091156cbd7beea724fbbdb25082.png)
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【推荐2】如图,在四棱锥
中,
平面ABCD,四边形ABCD为直角梯形,
,
,
,
,
,Q为PD的中点.
(1)求证:
平面ABQ;
(2)求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9060f03b9ee41d70d135b1e1a8902ce9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/829018a6ca0aff95d89e3f7cd943274e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3b10835116b9b777a666b438c907b49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be62ac0f5edb1eaebb5f491a7c30f97b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/29/c7371b22-a2c8-4812-ad5a-23ac01c531f1.png?resizew=138)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/534100c84d4561d2f156f7498e39e68e.png)
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名校
【推荐1】如图所示,在四棱锥
中,平面
平面
,底面
为矩形,
,
,
,点M在棱
上且
.
![](https://img.xkw.com/dksih/QBM/2022/3/6/2930519802462208/2933762734424064/STEM/41c5e812-4f90-464f-89b5-d643371667d0.png?resizew=193)
(1)证明:
平面
;
(2)求平面
与平面
的夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3912bd0b4aad85d86a46fb846cc04596.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34b416412f982d9c6956b2229d6e3729.png)
![](https://img.xkw.com/dksih/QBM/2022/3/6/2930519802462208/2933762734424064/STEM/41c5e812-4f90-464f-89b5-d643371667d0.png?resizew=193)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8c2b786c64e6a9ed2ec5670cde74f86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7f2e778c348154f5b27aa6e074fe45d.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7f2e778c348154f5b27aa6e074fe45d.png)
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【推荐2】如图1,在直角梯形ABCD中,AD∥BC,AB⊥BC,BD⊥DC,点E是BC边的中点,将△ABD沿BD折起,使平面 ABD⊥平面BCD,连接AE,AC,DE,得到如图2所示的几何体.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/2/442477fc-397f-4b5e-bac8-39da6dc77509.png?resizew=346)
若AD=1,二面角CABD的平面角的正切值为
,求二面角BADE的余弦值.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/2/442477fc-397f-4b5e-bac8-39da6dc77509.png?resizew=346)
若AD=1,二面角CABD的平面角的正切值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35361e76a7c85d1886728c8d0200b234.png)
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【推荐3】已知四棱锥
底面ABCD是矩形,PA⊥平面ABCD, AD=2,AB=1,E.F分别是线段AB.BC的中点,
(2)在PA上找一点G,使得EG∥平面PFD;.
(3)若
与平面
所成的角为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
(2)在PA上找一点G,使得EG∥平面PFD;.
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1e5fa72f2878b476bc57f0df12d6555.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d32c6f1f2d12161619aa3d15197ee5.png)
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