如图,在四棱锥
中,底面
是菱形,
,
,
,
底面
,
,点
在棱
上,且
.
(1)求证:
平面
.
(2)求二面角
的余弦值.
(3)求四面体
的体积.
![](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/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a23f01af749100e1888bba06268843db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3e126c16032892966489053f44b9048.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae890f9e8b32aa53a54158f24f4a87bc.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/4cc72a44dad13532cb9ddcc64bd78105.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/12/778aeaad-c5bf-4c02-850b-275be8f9db43.png?resizew=185)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56fdf217165748fafe938b64fa08179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5102c216393e133fa25dba98cd78535.png)
(3)求四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f178906e90bafd73e0ef9f89814855d5.png)
更新时间:2023-07-09 22:07:42
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相似题推荐
解答题-证明题
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适中
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名校
解题方法
【推荐1】已知正方体
中,E是
的中点,
是
的中点.
平面
;
(2)设正方体的棱长为2,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cfbc0b5a8fbde804bd8425a4b76d207.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f11f1840eb8b17e7b07c3fe7e987a9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
(2)设正方体的棱长为2,求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9c31176e441852e88e002aa65a5923d.png)
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【推荐2】如图1,在直角梯形ABCD中,
,
,
,E是AD的中点,O是AC与BE的交点.将
沿BE折起到如图2中
的位置,得到四棱锥
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/25/afcf2b45-159e-49f4-8a4a-0cca56632358.png?resizew=353)
(1)证明:
;
(2)当平面
平面
时,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce0d7095ddd69d6ceaf1065b1bc2c79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e62ca104bd39a1646922b5836f1826b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdfe7976bd3f16bfef5c6f1b4f20f23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2db2b1c641b93caae9b7a82441e4ba70.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/25/afcf2b45-159e-49f4-8a4a-0cca56632358.png?resizew=353)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ed2a23c5569ecf4ab6ccf927a4ab46f.png)
(2)当平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c44c1843ff6150ebc6aad3e34e477d2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f56aa9529f74055afd5a6c4bf5de86d.png)
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【推荐1】如图,在直三棱柱
中,
是正三角形,
是棱
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/14/f746cda1-6635-43d4-993b-ffd5802bd0e9.png?resizew=204)
(1)求证平面
平面
;
(2)若
,求点
到平面
的距离.
![](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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/14/f746cda1-6635-43d4-993b-ffd5802bd0e9.png?resizew=204)
(1)求证平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3837007567ab66f5cbe93ea39d6b259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ac61c24f99a4e466f1e2ea011893866.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0af405392c66b86550a58f1cb9868717.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea848cd2aa3a464618020475097949fc.png)
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解答题-问答题
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(0.65)
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解题方法
【推荐2】如图,PA⊥平面ABCD,四边形ABCD是矩形,PA = AB,点F是PB的中点,点E在边BC上运动.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/19/9f0ebe3a-9eab-4a91-ad8c-0caf16bb9ed0.png?resizew=165)
(1)当点E为BC的中点时,试判断EF与平面PAC的位置关系,并说明理由;
(2)证明:无论点E在边BC的何处,都有PE⊥AF.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/19/9f0ebe3a-9eab-4a91-ad8c-0caf16bb9ed0.png?resizew=165)
(1)当点E为BC的中点时,试判断EF与平面PAC的位置关系,并说明理由;
(2)证明:无论点E在边BC的何处,都有PE⊥AF.
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【推荐1】如图,球
的截面
把垂直于它的直径分为
两部分,截面圆
的面积为
,
是截面圆
的直径,
是圆
上不同于
、
的一点,
是球
的一条直径.
![](https://img.xkw.com/dksih/QBM/2020/11/23/2599184148979712/2600057159376896/STEM/55f177fbcf4a43c790864759ec2b2457.png?resizew=185)
(1)求三棱锥
的体积最大值;
(2)当
分
弧的两部分
弧与
弧的弧长之比为
时,求二面角
的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5881f1ce9b4172ca346032d0fd1e3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cb9c018281fcaaf52863e1f83d9dad0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://img.xkw.com/dksih/QBM/2020/11/23/2599184148979712/2600057159376896/STEM/55f177fbcf4a43c790864759ec2b2457.png?resizew=185)
(1)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37d65e051e943ab28fa57aee2fb57994.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c909cd1b6f3fa1ec39eb245e8f5c11c.png)
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【推荐2】如图,在三棱柱
中,
平面
为正三角形, 侧面
是边长为
的正方形,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/2803d4c7-4397-4140-a746-ececddd814d4.png?resizew=215)
(1)求证
平面
;
(2)求二面角
的余弦值;
(3)试判断直线
与平面
的位置关系,并加以证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be9ee7fff039524b6848147d14444b5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d25e8fc3dda4f8b45491514b6e22a962.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcaa21c6cc1086f121dbf9e39e52ec78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/2803d4c7-4397-4140-a746-ececddd814d4.png?resizew=215)
(1)求证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a22daf90ae241f084d526f7a6025926.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41104641f3e2260d00aeadf8fb8a078a.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/379c7b2495bdfcac49c1979bb14bcf5e.png)
(3)试判断直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41104641f3e2260d00aeadf8fb8a078a.png)
您最近一年使用:0次
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【推荐3】如图,在四棱锥
中,底面
是矩形,
是
的中点,
平面
,且
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/12/ee2b26db-04bb-4488-bf81-f8e26d6b8d2a.png?resizew=138)
(1)求证:
;
(2)求二面角
的余弦值.
![](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/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e4720bd0e6a1d47a84e19b60d4ea36c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/12/ee2b26db-04bb-4488-bf81-f8e26d6b8d2a.png?resizew=138)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b44f4120c94cb7176dc31fcac387b32e.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9e81c256be76e1d0a71a09a75fe91d8.png)
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