已知如图一
,
,
,
,
分别为
,
的中点,
在
上,且
,
为
中点,将
沿
折起,
沿
折起,使得
,
重合于一点(如图二),设为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/46b8dd19-1f97-4ef1-a34e-9ac41298b41c.png?resizew=280)
(1)求证:
平面
;
(2)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f8f88798ec42a58dccd212586382b23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08313da7b66283d2e0b3987f3e6761f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf4f947e0f238c37854afa0bf6b93a8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f2ea13010e2399194be2a681310543e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/46b8dd19-1f97-4ef1-a34e-9ac41298b41c.png?resizew=280)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1d0df73a49d4348a5c1e3aaa149cc8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fbbe7f48676298f2ee0cb1901992eaf.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c19de14651645718682d3d2af5993b0.png)
更新时间:2020-05-25 12:03:57
|
相似题推荐
解答题-证明题
|
较难
(0.4)
名校
【推荐1】在四棱锥
中,
,
,
,
为
的中点,
为
的中点,
.
(1)求证:
平面
;
(2)取
中点
,证明:
平面
;
(3)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed208e35a78c2659b552ca067b20b1c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b795caa147dfbd89ce4460253d025b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/502a46021ff0bd64fc4cd3bad7d8a826.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e2942390d02efaff57473d103f7950a.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd0285afe567ca0b32f0ccafc30167cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)取
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5f1897a7e856b42f8cee0f286ad913d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
(3)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
![](https://img.xkw.com/dksih/QBM/2017/11/10/1814292395573248/1815464619302912/STEM/017e73cb-3745-4f4a-8365-ceea6a406f3c.png)
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解答题-证明题
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较难
(0.4)
【推荐2】如图,已知四棱锥
,
且
,
,
,
,
的面积等于
,E是PD是中点.
![](https://img.xkw.com/dksih/QBM/2021/6/29/2753469786300416/2781031193870336/STEM/37dc3ed6-8a66-441e-993b-dff3af0ce8c3.png?resizew=282)
(Ⅰ)求四棱锥
体积的最大值;
(Ⅱ)若
,
.
(i)求证:
;
(ii)求直线CE与平面PBC所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef699f5dc072b853cfe700c6f1abbbae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a8751f226cdfbff4119a12c75a8df30.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d768ffd5bf75080e8ff5ce6b472c0cc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55a675310c8ba418e5a59beb7317e21e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/354ec8391bdd39377804ee4dab1d8f1c.png)
![](https://img.xkw.com/dksih/QBM/2021/6/29/2753469786300416/2781031193870336/STEM/37dc3ed6-8a66-441e-993b-dff3af0ce8c3.png?resizew=282)
(Ⅰ)求四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/185e2811de8461a7d5032872258bf433.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ea9995a58cbfbd0f8a5c712c2bcce4.png)
(i)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf6c62979a7aa534a191d8387a741e8.png)
(ii)求直线CE与平面PBC所成角的正弦值.
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名校
解题方法
【推荐1】如图,已知四棱锥
的底面为直角梯形,且满足
,
,平面
平面
.
为线段
的中点,
为线段上的动点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/13/883e0e91-385e-4811-9811-d4da07991c7e.png?resizew=170)
(1)求证:平面
平面
;
(2)设
,当二面角
的大小为60°时,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81c7c3fb46f6c07e5aefabaf9c5fa5b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/235d1553f6806c1eee3b17b94d23f0f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21665d21bbfb04410c78345de1fd15ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c2bc5e50b8dfa02601c70822252854a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/13/883e0e91-385e-4811-9811-d4da07991c7e.png?resizew=170)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/235d1553f6806c1eee3b17b94d23f0f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97245dc4a30ac7e03f6b55d5b2f4401b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/496eefb185e0ed09af5655772958ae9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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解题方法
【推荐2】图,在三棱台
中,
是等边三角形,
,侧棱
平面
,点D是棱
的中点,点E是棱
上的动点(不含端点B).
(1)证明:平面
平面
;
(2)求平面
与平面
的夹角的余弦值的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ee6b48346072cb2dd3df26cf733f010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a8bfe2553e852df73185d017c0a62fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/30/7f30a3f1-1a52-454c-8e3a-52b0bbc4bbfc.png?resizew=160)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce04b35c265cc9c48b60204bd2f718ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be0ca7c25eceffc1c3515446f59396e1.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
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解答题-问答题
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较难
(0.4)
【推荐3】如图1,在边长为4的等边三角形ABC中,D,E,F分别是AB,AC,BC的中点,沿DE把
折起,得到如图2所示的四棱锥.
![](https://img.xkw.com/dksih/QBM/2022/1/7/2889217549983744/2889834336264192/STEM/760fd5e4-f343-440f-ba9a-0cb27f3e2cb5.png?resizew=292)
(1)证明:
平面
.
(2)若二面角
的大小为60°,求平面
与平面
的夹角的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://img.xkw.com/dksih/QBM/2022/1/7/2889217549983744/2889834336264192/STEM/760fd5e4-f343-440f-ba9a-0cb27f3e2cb5.png?resizew=292)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06222ee533c2484ab25321a6abbf98cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/628d6fc46c651e0c783b81a123a7b229.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9afac7c616bbb14e1ed428a3c507c7dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f233b375753611ffa7a93c2c12ef5e28.png)
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