已知
,
分别为等腰直角三角形
的边上的中点,
,现把
沿
折起(如图2),连结
,得到四棱锥
.
![](https://img.xkw.com/dksih/QBM/2016/7/22/1572929416380416/1572929422696448/STEM/4d14701f-a150-46d2-9a09-5c3eb4958eff.png?resizew=249)
(1)证明:无论把
转到什么位置,面
面
;
(2)当四棱锥
的体积最大时,求
到面
的距离及体积的最大值.
![](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/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1c9e2fbfea1fafe33d98048a52772e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63df0f5cad1a1d8c5e6ae5f3bc8f837b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dec2ca6438c82b43f746057d8129885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a77254d2773dfaee5d13f77e5ec39e9.png)
![](https://img.xkw.com/dksih/QBM/2016/7/22/1572929416380416/1572929422696448/STEM/4d14701f-a150-46d2-9a09-5c3eb4958eff.png?resizew=249)
(1)证明:无论把
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63df0f5cad1a1d8c5e6ae5f3bc8f837b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/004dd8ad9e5a200b3869ebfc59c2446d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f233b375753611ffa7a93c2c12ef5e28.png)
(2)当四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a77254d2773dfaee5d13f77e5ec39e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f6b1a6adac644c48cab9ec4d392a152.png)
更新时间:2016-12-04 17:16:00
|
相似题推荐
解答题-证明题
|
较难
(0.4)
名校
【推荐1】如图,已知三棱台
的体积为
,平面
平面
,
是以
为直角顶点的等腰直角三角形,且
,
平面
;
(2)求点
到面
的距离;
(3)在线段
上是否存在点
,使得二面角
的大小为
,若存在,求出
的长,若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e57f00c8225a33458a6b62bff0dcc16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85a2e10a5aebe40a9018d5ee3ade7af8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67fe4be64d44a1213970572a04eb5fcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
(2)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
(3)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f637bf133818d36ad04ce78d3a6cc80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/037fb348109dc2063a268b10eb925a57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
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【推荐2】已知三棱锥
中,
,
,
,
为等边三角形,平面
平面
,
为
的中点
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/6a75a23a-9084-44ec-944e-308277f968ae.png?resizew=158)
(1)求证:
平面
.
(2)若
为
的中点,求三棱锥
的体积.
(3)(只理科做)求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b59ab6bf6111dda4a3d428454768b77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63ab13ef156d034b710d811e09b0be34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/6a75a23a-9084-44ec-944e-308277f968ae.png?resizew=158)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71719fa9855745e17362dc00fe945ce2.png)
(3)(只理科做)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6ea6e7aec788b4a60aeabdb948a95c6.png)
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【推荐3】如图所示,四边形
为菱形,
,平面
平面
,点
是棱
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/11/c44bd8a6-5ee1-409d-a506-0e63aadc7395.png?resizew=169)
(1)求证:
;
(2)若
,求三棱锥
的体积.
(3)若
,当二面角
的正切值为
时,求直线
与平面
所成的角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62974d34de3a12418d6b700420afd1b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d78fc7fcb2762de28dcef8aa3aa0e49.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/2023/2/11/c44bd8a6-5ee1-409d-a506-0e63aadc7395.png?resizew=169)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5bc56fdf70e65bd88980c64af96b83da.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91b1fa95e2d4cff19c511e77ad83eabd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0199f36fcea2e8321aba196ec9cb8de.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/829f9180ddd9aa1a0ee0dc520f4e0b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf29d07c3751c41ab3503065a5a5052e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274a9dc37509f01c2606fb3086a46f4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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解题方法
【推荐1】利用定义法、向量法证明直线与平面垂直的判定定理:如果一条直线与一个平面内的两条相交直线都垂直,那么这条直线垂直于这个平面.
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解题方法
【推荐2】如图
所示,在边长为
的正方形
中,点
在线段
上,且
,作
,分别交
于点
,作
,分别交
于点
,将该正方形沿
折叠,使得
与
重合,构成如图
所示的三棱柱
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/30/0629ea74-acec-43cf-a144-f998f198a80a.png?resizew=372)
(1)在三棱柱
中,求证:
平面
;
(2)试判断直线
是否与平面
平行,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8da45c443af7994a26ffa9d8894e7262.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8948a21ea27a2b5597732fe55eae040.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0520e9675bc1b416e8b8f01eb69fd13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24963d5acbbdcd6e15c2db04002e0909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32b4da8d254b7d76b7615d7f7cd824a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa742d9b84b537be10034553776400e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e17591f330b50e309f3965fdf1b1404.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55bbaa1871038341321f574e6e22597e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/074151243328c355493e0f2886d9b4f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e17591f330b50e309f3965fdf1b1404.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c827526ebb2b5ae980039762d6c0cdc0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ebf67d880172b27fefacc3c5b808eae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2faf407a5a827fc4291b898d324b9ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab917cf28081f6a5e53430bf89cdd8dc.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/30/0629ea74-acec-43cf-a144-f998f198a80a.png?resizew=372)
(1)在三棱柱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab917cf28081f6a5e53430bf89cdd8dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
(2)试判断直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84d454c82d9e52747563d47b68099249.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99f488b85184d4e9d5fc9ccd0cfda8c5.png)
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【推荐3】如图,在三棱柱
中,侧面
为矩形.
为
中点,点
在线段
上,且
,求证:
平面
;
(2)若二面角
的大小为
,且
,求直线
和平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c3073cfd9ace3affad3f8ea6824f84c.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b8771e5813d081e1da7acca1ced4947.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c19129982fd8389238b303e091bd94c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfaf581b4f42a25087f7eee23a7d66b6.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cfa5b176fd1316fb676bbee21cc5f02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac1a63ab608517bb10aa036783dfb51f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f74a61581d965458316280968241e4c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13779894af95274a6a3158907dc8bfd6.png)
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解题方法
【推荐1】如图,已知三棱柱
,
,
,
为线段
上的动点,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/15/5b11a190-88a3-4bf1-8b34-95aca592ba53.png?resizew=156)
(1)求证:平面
平面
;
(2)若
,D为线段
的中点,
,求
与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae1c13645081be951f709fa743a65084.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0aa142bb96af98b846997e681609739f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/15/5b11a190-88a3-4bf1-8b34-95aca592ba53.png?resizew=156)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61cdaadeae37736a1e6dd93fa1fe712f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02864602e30b261c2de2fffb52193a92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7dc39e2113669164b4894c2ef739f0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87cdc08e1c4a04a18d5ecea03393e36d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9afac7c616bbb14e1ed428a3c507c7dc.png)
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【推荐2】如图,在三棱柱中,侧面
是矩形,
,
,
,且
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/6/fc5812d0-79a6-477a-bea9-a91a591417f8.png?resizew=149)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/140088b0cb73812aa9d523c44559298a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e53b212640dadf751ef7f65a78a209.png)
(2)设D是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f1f229274a6e17977cc047814212589.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/063510e3c1fb6a7ccc3b8e3e3c7d660e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea848cd2aa3a464618020475097949fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea848cd2aa3a464618020475097949fc.png)
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