在三棱柱
中,
,
,
,
平面
,
与平面
所成的角为45°.E,F分别是AC,
的中点.
![](https://img.xkw.com/dksih/QBM/2022/1/17/2896547389702144/2901543236083712/STEM/33334f9e-b3d3-4460-a481-9a86285469ab.png?resizew=225)
(1)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
平面
;
(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/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e89195bacd53d43195e70c12b5cfa041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1859959fdb4c5edd8056893f94a10a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://img.xkw.com/dksih/QBM/2022/1/17/2896547389702144/2901543236083712/STEM/33334f9e-b3d3-4460-a481-9a86285469ab.png?resizew=225)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07b7903de4be7d5dc1175cfbf6e8da9f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b08b27dcf51ffda14dea4b572c907db.png)
更新时间:2022-01-24 20:27:44
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,四棱台中,底面
为正方形,
平面
,且
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/926b9841-463d-4f8f-a06d-be9a97d6a951.png?resizew=230)
(1)证明:
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a211ad5a06b505b8365a62c1946f3cb7.png)
;
(2)若直线
与平面
所成角的正弦值为
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/498c8dc5ec5f261af83b3c939bd5f0bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/570f8b295ee0c7c60e6fe1dbf054ff52.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/926b9841-463d-4f8f-a06d-be9a97d6a951.png?resizew=230)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2164a9dd77a54b1999a0f5ab0ecf09df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a211ad5a06b505b8365a62c1946f3cb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e45bcd8f6ede8cc2513ad41402f40086.png)
(2)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38883dac3173ebd62d93004489be1999.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a211ad5a06b505b8365a62c1946f3cb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d86ab7c97cd8a0b15ba5efc1be94230.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
您最近一年使用:0次
解答题-证明题
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(0.65)
名校
解题方法
【推荐2】如图,三棱锥P﹣ABC中,PA,PB,PC两两垂直,PA=PB=PC,且M,N分别为线段AB,PC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/20/4e4f2e34-51a0-4919-8300-810c9411292e.png?resizew=185)
(1)若点K是线段PM的中点,求证:直线
平面ABC;
(2)求证:平面PCM⊥平面ABC.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/20/4e4f2e34-51a0-4919-8300-810c9411292e.png?resizew=185)
(1)若点K是线段PM的中点,求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/182c5b2235750b3d58f1b383657ac22a.png)
(2)求证:平面PCM⊥平面ABC.
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解答题-证明题
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适中
(0.65)
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【推荐1】如图,在直三棱柱
中,D点为棱AB的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/30/baa2bc47-f5a8-406a-9620-37c417657f1e.png?resizew=167)
(1)求证:
平面
;
(2)若直棱柱的所有棱长均相等,求二面角
的平面角的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/30/baa2bc47-f5a8-406a-9620-37c417657f1e.png?resizew=167)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89006cac018a9875f65ed7bd429c61bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbc7e774e4ae40c23bf4ceed179230ca.png)
(2)若直棱柱的所有棱长均相等,求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55089af69fcfa82c2a34df1b4e1cabf0.png)
您最近一年使用:0次
解答题-证明题
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适中
(0.65)
名校
解题方法
【推荐2】如图在四棱锥
中,
底面
,且底面
是平行四边形.已知
是
中点.
![](https://img.xkw.com/dksih/QBM/2022/12/24/3137936047071232/3139194309517312/STEM/cc03dc2bfe9047aca7177b99a29ad866.png?resizew=189)
(1)求证:平面
平面
;
(2)求平面
与平面
所成锐二面角的余弦值.
![](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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54ffcabd60d67dddcf2ea651411e7301.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/2022/12/24/3137936047071232/3139194309517312/STEM/cc03dc2bfe9047aca7177b99a29ad866.png?resizew=189)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78a3fd5284e160896f07ce367645fd04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
您最近一年使用:0次
解答题-证明题
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适中
(0.65)
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【推荐3】如图,四棱柱
中,底面
为正方形,
与
交于点
,平面
平面
与底面
所成的角为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/3/a39345cf-4fff-4dc3-8d6e-86d809b51761.png?resizew=187)
(1)求证:
平面
;
(2)求平面
与平面
的夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91ba5715a95b8de18c637c12c3d30d7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/becd78173aa4b297b78a19ac6a036456.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d5bca00fa20e6e80480b9d06d2e52ee.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/3/a39345cf-4fff-4dc3-8d6e-86d809b51761.png?resizew=187)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c1ad2917b716db41c03e670f77d411d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13cfdc6224181d44e63aab43ddaf07ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82b724168afaee2ecddf97257180be18.png)
您最近一年使用:0次