如图,四棱锥
中,
底面
,
,
,
,
,
为棱
上的点,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/f450cb25-a7a2-4c38-acf7-f1f5d65230f7.png?resizew=219)
(1)证明:平面
平面
;
(2)求二面角
的大小.
![](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/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a0e5697eca3f5205cb7b343648240bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d262480ffb55b7617f44b63f130c154a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99d24703c6de41c2df507d5405f377ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d4db9b82b67efe45a02fca32bfcf5dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a82a8bc0e66fd0bd01a8f0c807be31a5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/f450cb25-a7a2-4c38-acf7-f1f5d65230f7.png?resizew=219)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3cc2b3a37ddb402589bd04351247a1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21665d21bbfb04410c78345de1fd15ae.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51e231505648333857565accb0c3c898.png)
更新时间:2021-07-27 08:34:31
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,正三棱柱
中,
分别是棱
上的点,
.
证明:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c95c0160e73beb94a4a1cbc0168e9a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e80c9702720a88f4a31c0484c7ff5c6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/21/6117341e-f2b0-4d70-abcc-704c3f513008.png?resizew=130)
证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3599e2d14048d66477e736223dd591d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
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【推荐2】如图所示,四棱锥
中,底面
是矩形,
底面
,
,
,点F是
的中点,点
在边
上移动.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/109bddd6-37bc-4129-a27b-76aee2a8d8b5.png?resizew=174)
(1)点
为
的中点时,试判断
与平面
的位置关系,并说明理由;
(2)当
为
中点时,求异面直线
与
所成角的余弦值;
(3)求证:无论点
在边
的何处,都有
.
![](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/0e7b6d04f024ca05cdfacc8ce9137c15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d783fe7f3ce673d5d21281174e7a7968.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/109bddd6-37bc-4129-a27b-76aee2a8d8b5.png?resizew=174)
(1)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(3)求证:无论点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a395778dcf588264f40e1cd8c96206d.png)
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【推荐3】如图,多面体
中,
两两垂直,且
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/27813c07-76d2-4cab-8733-337fa252e5b0.png?resizew=167)
(1)若点
在线段
上,且
,求证:
面
;
(2)若点
在线段
上,当直线
与平面
所成角的正弦值为
时,求线段
的长;
(3)求锐二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f74fcff24edb5c3c44894023dbfdc78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c91baecb97fadd4f8ab49e6effcbc04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cef0f4f2fa1f55c4d82d11ac48566489.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a77f26a7be722e00baa984f769ec8d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8fc3ee9005673e5ed0eb7a1b5a5b479.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/27813c07-76d2-4cab-8733-337fa252e5b0.png?resizew=167)
(1)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00db9b6ae3f7d52673bd15b516a66cf1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f220434c51562f59e302899804899954.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fa3254460ecbacecb3e57c5dce227f4.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fa3254460ecbacecb3e57c5dce227f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faa00709db52164ca2d290e55b4dbc0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
(3)求锐二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d243d9a135116a6749d586fd5b95ec73.png)
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解题方法
【推荐1】如图,在四棱锥
中,四边形
为平行四边形,
为等边三角形,点
为
的中点,且
.
![](https://img.xkw.com/dksih/QBM/2021/4/22/2705340084658176/2711851711954944/STEM/7f6fef89-ddc8-4ebf-9218-4d9c91ed3f3b.png?resizew=255)
(1)证明:平面
平面
;
(2)若
,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80c753cb1eb73fd8d136d00462970797.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbfa1a2af7e38d33634c462300df381f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05385a6b2a32bbf6d43395bc20d9031c.png)
![](https://img.xkw.com/dksih/QBM/2021/4/22/2705340084658176/2711851711954944/STEM/7f6fef89-ddc8-4ebf-9218-4d9c91ed3f3b.png?resizew=255)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed5f0cfc1049f84a04c81bd213afb8d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/500df0e782bb081e608f4bc1d576afcf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48a277db452e76240ec83ec6a2864bdd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1e52b5625cff6fc8c5e150dd02a6e4b.png)
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真题
【推荐2】如图,在四棱锥
中,底面ABCD为矩形,
底面ABCD,E是AB上一点,
.已知
,求:
(2)二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f22f74a1995a5b5fa2a0536606ce1df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3369e508d37666786ad9bff5905f14e.png)
(2)二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08b0dc4f92cba842f44477bc9811065c.png)
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