如图,在正三棱柱
中,D,E分别为棱
的中点,
在棱
上,且EF
平面
.
(1)求
的值;
(2)若
,求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e79a03b1084cb2e8f8ac00329fe98544.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ba9e20d667d04bf3ee7f55cc795ce01.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/9/126fd3df-55c0-470f-8355-d5096437a597.png?resizew=138)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5c8ae2f62d6a56f0ad6104814e73e50.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eeed487430a5b8a330f2d0c52166521a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a8035fc825a001d7d9a3dacd8271662.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bff3ccea5989c60e51e321af3f53f54.png)
更新时间:2024-03-09 18:37:20
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,四棱锥
的底面
中,
为等边三角形,
是等腰三角形,且顶角
,
,平面
平面
,
为
中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/2c984f19-e350-41d0-a287-3bfc7338ab3c.png?resizew=168)
(1)求证:
平面
;
(2)若
,求二面角
的余弦值大小.
![](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/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5b0382c28547d3834ca71f3f0677695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4125524caac016727c80d2722c5ba3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f04c222223dae9ef27d4c132534d9848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/2c984f19-e350-41d0-a287-3bfc7338ab3c.png?resizew=168)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ba8f7af0e091e082100c3cd7f8c487f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/371853a703a8dafa6f8e942f46cb8706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74ec3d90e5f12cd8946d4dc638c1a357.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】如图,在长方体
中,
,点
是棱
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/c559314d-5189-4d95-93c1-459682df7b71.png?resizew=198)
(1)证明:
;
(2)求直线
与
所成的角;
(3)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ed1da7a28fb1983af25f2be2ed03cd3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/c559314d-5189-4d95-93c1-459682df7b71.png?resizew=198)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0fa81c1f81266b4ef3d471bc6bfc38d.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10d8eb4a9f462ca0c1d49c3fe91e720d.png)
(3)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35988677892d6ffdf4773f7a861f26a4.png)
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解答题-证明题
|
适中
(0.65)
【推荐3】如图,三棱柱
中,
面
,
为
的中点.
(1)求证:
面
;
(2)求二面角
的余弦值;
(3)在侧棱
上是否存在点
,使得
面
? 并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62996650dd61ab72975c0b238ed2c203.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b5bfd70c87a325a9491404bb0d397d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/111e7f12b82c1e650511a9e006e4ad78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bf9628142422a4884bd59538da6d312.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd190b5a26dfb45a06c1d6ee86dd82d9.png)
(3)在侧棱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e245440d3761fb4217eaa8dc303fa288.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bf9628142422a4884bd59538da6d312.png)
![](https://img.xkw.com/dksih/QBM/2010/12/20/1569941239939072/1569941245116416/STEM/a4453187-1430-4933-8f5b-f69314c0b569.png?resizew=208)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】已知四棱锥
的底面为直角梯形,
,
,
平面
,且
,
是棱
上的动点.
(1)求证:
;
(2)求证:平面
平面
;
(3)是否存在点
使得
平面
,若存在请求
的值,若不存在请说明理.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68d31600cba2d5256c7e78b6122d6755.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2b377f22aafd3742ad860f77abaacef.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/bda1a7eeb84ee2f5f723c78de0867aa1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/15/479a11c5-884a-4977-add6-4d1dd4532a6a.png?resizew=200)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b44f4120c94cb7176dc31fcac387b32e.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(3)是否存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36222db36e348661eb5f616820e4e60f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af68a7bf0da4f7c6f739d2e2461ad9b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f59a8e73d86982a4882510a179b0efb0.png)
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】如图所示,正方形
的边长为
,
、
分别为
、
的中点,
、
是平面
同一侧的两点,
平面
,
,
.
![](https://img.xkw.com/dksih/QBM/2020/12/6/2608413667966976/2609223078838272/STEM/3f054667dc6a452cab4a36367e2f59ac.png?resizew=358)
(1)设
,
为
上一点,若
平面
,求
;
(2)证明:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95bacae35b6e16a0a33c2bdc6bc07df7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.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/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39967d6f3aed6ce7b6643787795d451d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de2eae6af16797f2ab8efc6041806677.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3de3236e61ff954df9dd9872bf7d95e3.png)
![](https://img.xkw.com/dksih/QBM/2020/12/6/2608413667966976/2609223078838272/STEM/3f054667dc6a452cab4a36367e2f59ac.png?resizew=358)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a23f01af749100e1888bba06268843db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dafebaaf13781120dc57c277d0267c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ae7bf236e8637182a1553ce36bd9c67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94cc30d46b4538a4c86064df7460356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3892b3fc0601d3a4b567fac01d9b2a0.png)
(2)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae1f07df5692e4c4e2db643aefdd0d98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94cc30d46b4538a4c86064df7460356.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐3】如图,在直三棱柱
中,
,
,
,点
分别是
的中点,点
是线段
上一点,且
平面
.
(1)求证:点
是线段
的中点;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/883fc5e3faf39829d60804b59deb1730.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ef8866ccf160ddc441bf69c5d3a3d5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1857eadd6b23a87a1a5b4ffff584efd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edc674d2604ff270dd6abc66b35e86e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ac61c24f99a4e466f1e2ea011893866.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/30/34b42285-132b-4679-a7bd-3aa9001c5480.png?resizew=126)
(1)求证:点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8c044d4c8a326a2270449a89304ff65.png)
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