如图,四棱锥
中,底面
是边长为2的正方形,
,且
,
为
中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/23/c3294898-47dd-434f-8f76-bb0176ac39d5.png?resizew=238)
(1)求证:
平面
;
(2)求二面角
的平面角的余弦.
![](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/25f425bed2507ed2bab9f1f636ba11da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/298833cdd868508ff8e2e4ce52ea45d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/23/c3294898-47dd-434f-8f76-bb0176ac39d5.png?resizew=238)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42f4096ff62b4f29932cd8c6eef661a3.png)
更新时间:2017-10-07 16:41:35
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相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,在四面体A-BCD中,已知平面
平面BCD,
为正三角形,
为等腰直角三角形,其中C为直角顶点,E,F分别为校AC,AD的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/89a128f0-bed4-49f9-aacd-515ee99c3283.png?resizew=175)
(1)求证:
平面BEF;
(2)求证:
平面ACD.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3d7090639341730951c1bc3c9b6164e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/89a128f0-bed4-49f9-aacd-515ee99c3283.png?resizew=175)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6785c7c85a503531649f9c9b4cbfcf04.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/662698361c6b3ddaf0c28a3c87be53e0.png)
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【推荐2】如图,在四棱锥
中,底面ABCD是矩形.已知
,
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/20/b56eac7a-e072-472e-8e8c-1136e6f5aaf3.png?resizew=212)
(1)证明
平面PAB;
(2)求异面直线PC与AD所成的角的大小;
(3)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efc6e4b936d7a800e839a30c3839574d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b80ee363635d73f601654339028daec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed6281306726065e7075c579b9b66537.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63e4d19bf237a6fca67e0d01a9ddb726.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/20/b56eac7a-e072-472e-8e8c-1136e6f5aaf3.png?resizew=212)
(1)证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
(2)求异面直线PC与AD所成的角的大小;
(3)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/053af8641980763a7f0e77beefe0712d.png)
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【推荐3】如图,
为圆
的直径,点
在圆
上,
,矩形
和圆
所在的平面互相垂直.已知
,
.
(1)求证:直线
平面
;
(2)求直线
与平面
所成角的大小;
(3)当
的长为何值时,二面角
的大小为
?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cf9b288c48c73463a2f214f02b6952a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0782b64e9a9e02436620c9421b32d6c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4901a7eda97d6a307db76c4fb196ba3d.png)
(1)求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fa3c61d6c19e187b4b824b6f5610cdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c93a34cbd4c0dc198b74524c0e05a10.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/603c7e98deecdba0cf3773757a9b8304.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a8ac50220c237d2bde9c4a30c711101.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
![](https://img.xkw.com/dksih/QBM/2011/12/9/1570565427322880/1570565432786944/STEM/921571b3-4ef1-4cc1-b405-bc748f81e690.png?resizew=172)
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解答题-证明题
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解题方法
【推荐1】如图,正四棱锥S-ABCD的底面是边长为2的正方形,侧棱长为
,P为侧棱SD上的点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/12/155a18a5-166c-41e0-8c21-b566acf41aa3.png?resizew=255)
(1)求证:AC⊥SD;
(2)若SD⊥平面PAC,求二面角P-AC-D的大小;
(3)在(2)的条件下,侧棱SC上是否存在一点E,使得![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
平面PAC?若存在,求
的值;若不存在,试说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95bacae35b6e16a0a33c2bdc6bc07df7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/12/155a18a5-166c-41e0-8c21-b566acf41aa3.png?resizew=255)
(1)求证:AC⊥SD;
(2)若SD⊥平面PAC,求二面角P-AC-D的大小;
(3)在(2)的条件下,侧棱SC上是否存在一点E,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9013fec36586592a57b9abfb6ce4ffa.png)
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【推荐2】如图,已知菱形ABCD的边长为2,
,S为平面ABCD外一点,
为正三角形,
,M、N分别为SB、SC的中点.
![](https://img.xkw.com/dksih/QBM/2011/5/11/1570192032202752/1570192037199872/STEM/94acc631-c145-44c0-9dc2-7c930afc998a.png?resizew=300)
(1)求证:平面
平面ABCD;
(2)求二面角A—SB—C的余弦值;
(3)求四棱锥M—ABN的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b22e2a74105e80896c441d940d08540.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e851cf27f94ac130d849e0b83af75528.png)
![](https://img.xkw.com/dksih/QBM/2011/5/11/1570192032202752/1570192037199872/STEM/94acc631-c145-44c0-9dc2-7c930afc998a.png?resizew=300)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/877582b5387278008d14fe5932622fe7.png)
(2)求二面角A—SB—C的余弦值;
(3)求四棱锥M—ABN的体积.
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【推荐3】如图,圆锥的底面圆心为O,直径为AB,C为半圆弧
的中点,E为劣弧
的中点,且AB=2PO=2
.
![](https://img.xkw.com/dksih/QBM/2022/4/7/2952947984433152/2958771169550336/STEM/def18c9be9ab4a4caa164e1676e4ca39.png?resizew=207)
(1)求异面直线PC与OE所成的角的大小;
(2)求二面角P﹣AC﹣E的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16d65cecaf8a3dc2953f4109c75a981e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82f95817a8ecb0cdea4e20bfd9911ad1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://img.xkw.com/dksih/QBM/2022/4/7/2952947984433152/2958771169550336/STEM/def18c9be9ab4a4caa164e1676e4ca39.png?resizew=207)
(1)求异面直线PC与OE所成的角的大小;
(2)求二面角P﹣AC﹣E的余弦值.
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