图①是由矩形
和梯形
组成的一个平面图形,其中
,
,点
为
边上一点,且满足
,现将其沿着
折起使得平面
平面
,如图②.
(1)在图②中,当
时,
(ⅰ)证明:
平面
;
(ⅱ)求直线
与平面
所成角的正弦值;
(2)在图②中,记直线
与平面
所成角为
,平面
与平面
的夹角为
,是否存在
使得
?若存在,求出
的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dde327febef2331a4766a79b433cc02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abe457d83a45da9c3af435a1a1319b2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d7882853e3d1122a57cc4beb8eecafd.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/9ca8d94c6437cdd63c48c05760ef6705.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cf9a6db3571fa57bfa2d5e4d44c51b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dde327febef2331a4766a79b433cc02.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/16/6afff234-fbdc-4cd1-af2c-c39acc2c7bed.png?resizew=356)
(1)在图②中,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73b3cf0f585938ede9eca890a6eb326d.png)
(ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071159cac13097ea0928285bc1be66d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24dc8826770249f3996b8a188c03da92.png)
(ⅱ)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffe8a84ca3a13f82aff1a022edc66065.png)
(2)在图②中,记直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffe8a84ca3a13f82aff1a022edc66065.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25f64fa38725c136504f723019a18dc5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90131175c3fb6a3837a22d7d5bbc268d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffe8a84ca3a13f82aff1a022edc66065.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e93fa313adc4ac7608ba9449fd755212.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/382184a43e2155e54abfa48ce96ad364.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
23-24高二上·四川成都·开学考试 查看更多[3]
四川省成都市蓉城名校联盟2023-2024学年高二上学期入学联考数学试题(已下线)专题8.9 空间角与空间距离大题专项训练-举一反三系列(已下线)第八章 立体几何初步 单元复习提升(易错与拓展)(2)-单元速记·巧练(人教A版2019必修第二册)
更新时间:2023-09-13 19:24:02
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相似题推荐
解答题-问答题
|
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【推荐1】【2018衡水金卷(三)】如图所示,在三棱锥
中,平面
平面
,
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/9/ab5469d8-e4f9-4991-96f7-32fa9f09b7fb.jpg?resizew=181)
(1)证明:
平面
;
(2)若二面角
的平面角的大小为
,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cad7b03f934718b18ce34cdf0b85863.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/991ec04fb924fd2407b679f56645126e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/413240c7a387889f4e5ffdb72e271a67.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/9/ab5469d8-e4f9-4991-96f7-32fa9f09b7fb.jpg?resizew=181)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56fdf217165748fafe938b64fa08179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b60870baa5e3fbc33a749aa5f0a94be.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b33b7213d99a817bff19bcf740a0697c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d2dff5ed9baa18e33592a52f8b9626f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
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【推荐2】如图,四边形ABCD与BDEF均为菱形,
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/27/fa88d288-8d04-4c31-ab29-9988ebe30a89.png?resizew=187)
(1)求证:AC⊥平面BDEF:
(2)若M为线段DE上的一点,满足直线AM与平面ABF所成角的正弦值为
,求线段DM的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f51d630183a57ea3f82f1db53a542ede.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6da20f949db06cbc10f052a7f8466019.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/27/fa88d288-8d04-4c31-ab29-9988ebe30a89.png?resizew=187)
(1)求证:AC⊥平面BDEF:
(2)若M为线段DE上的一点,满足直线AM与平面ABF所成角的正弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57519125aaed7afca4d6a45102c517a3.png)
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【推荐1】如图所示,四棱锥
中,
底面
,
,
为
中点.
(1)试在
上确定一点
,使得
平面
;
(2)点
在满足(1)的条件下,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ffe1ac7a3d608efeaac811e992dcf98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa9d7ff689d4307f576725374a4ae94a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
(1)试在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcf19a7f0dd0cdf59516ae585025110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://img.xkw.com/dksih/QBM/2017/8/19/1755663809503232/1756253125935104/STEM/46a483635b2047d0b16d891d36819118.png?resizew=140)
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【推荐2】如图,在矩形ABCD中,
,点M在边DC上,点F在边AB上,且
,垂足为E,若将
沿AM折起,使点D位于
位置,连接
,
得四棱锥
.
![](https://img.xkw.com/dksih/QBM/2018/12/10/2093856129302528/2095725079855104/STEM/9ade1951577c434783170c57d268eb8a.png?resizew=530)
Ⅰ
求证:
;
Ⅱ
若
,直线
与平面ABCM所成角的大小为
,求直线
与平面ABCM所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f599f4cc8aa51780501732698705952e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/386e95a335cc9a7bb2676a050b3c7037.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e2bd387ad688461e522af5acf2108d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c51b7c6787b9d03405710d9dada1fc90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b81b2887836854aad88468cf4ebf5b6c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce0f2f0105defbc9e3cacfd9d5a66d75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/106adc8c665d11161384913575c3e613.png)
![](https://img.xkw.com/dksih/QBM/2018/12/10/2093856129302528/2095725079855104/STEM/9ade1951577c434783170c57d268eb8a.png?resizew=530)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcb37021d05c1d5ebc18d97c6ab5d7d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14015f43321d8ba5b95b34a25e0ece59.png)
![](https://img.xkw.com/dksih/QBM/2018/12/10/2093856129302528/2095725079855104/STEM/757fc558c1544ddb8edff6bbfd4b3830.png?resizew=31)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65af1d6b6b831ebbdc36dda5f304a3a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af0bb45d247759c0bc34af747c7bfd1f.png)
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【推荐3】如图,在四棱锥
中,底面
为正方形,侧面
是正三角形,侧面
底面
,E是
的中点.
(1)过点E在面
内画一条直线l,使得
,写出做法,并说明理由;
(2)设直线l与
交于F点,求
与底面
所成角的正弦值.
![](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/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/25/e556d65b-b8e6-43c7-a5d1-fb241d928f56.png?resizew=170)
(1)过点E在面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e091f5bbf66bd625cb1adab21d8c75b.png)
(2)设直线l与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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【推荐1】如图,在四棱锥
中,底面
为矩形,平面
平面
为
中点,
与
交于点
的重心为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/10/9b357987-9137-4b63-9ea6-04afe4af86aa.png?resizew=178)
(1)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)若
,求二面角
的正弦值.
![](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/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbd6f10ececa5670a3cf2f6b3348d82a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/683c590673eece14fea3319c4fd5eb55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a369e96207ddf8e489751852abcd73f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/10/9b357987-9137-4b63-9ea6-04afe4af86aa.png?resizew=178)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dde36f2493881e4c8027a8aeb908b886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dba5bc0ae7fd9f2a903415cc83c286e5.png)
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【推荐2】如图,直四棱柱
中,底面ABCD是
的菱形,A
,AB=2,点E在棱C
上,点F是棱
的中点;
(Ⅰ)若E是CC1的中点,求证:EF∥平面A1BD;
(Ⅱ)求出CE的长度,使得A1﹣BD﹣E为直二面角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76a91116b13468941d08445b2611bbcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa0c3c54ad91c0bed7599f2f499f3e31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9dfac63840693baae1725bc53c790bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afb6101e45f8d7013bc3dc4197188c0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5aa62b5a161c20430cb1dda9809247f3.png)
(Ⅰ)若E是CC1的中点,求证:EF∥平面A1BD;
(Ⅱ)求出CE的长度,使得A1﹣BD﹣E为直二面角.
![](https://img.xkw.com/dksih/QBM/2012/1/12/1570686276968448/1570686282399744/STEM/a93ce8c33d5a45d286660770853aa521.png?resizew=201)
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【推荐3】如下图,四棱锥
的体积为
,底面
为等腰梯形,
,
,
,
,
,
是垂足,平面
平面
.
;
(2)若
,
分别为
,
的中点,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5acb763021bf166ca719d07223591d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/279e119eed905cf15026649a1b86502a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a398397362a18da1cc9f24bf3f356ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f29c3e772e56008790298824122792.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7713c13736076f1fe2c139bb4a4b6d6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9104a1941e557a85fd1496bc2b9be297.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99ab98efd2b5fcbfeae61fe37f921a0e.png)
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解题方法
【推荐1】矩形ATCD中,
,
,B为TC的中点,
沿AB翻折,使得点T到达点P的位置.连结PD,得到如图所示的四棱锥
,M为PD的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/9/17efd663-65fe-49b2-b3bb-aa48d577778f.png?resizew=361)
(1)求线段CM的长度;
(2)若平面
平面ABCD,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04ee826937d2add7a93aaa1422f8b736.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40560ea08d6cd8c1d4d9661ee6faaa3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a04e30d5827f2120d997997e4e31ba17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/9/17efd663-65fe-49b2-b3bb-aa48d577778f.png?resizew=361)
(1)求线段CM的长度;
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddfe0ccf24d760c77535a70c92dad145.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,三棱锥
中,
,
,
.
![](https://img.xkw.com/dksih/QBM/2021/1/30/2647464178663424/2650174873886720/STEM/22da8196b6d14219a9525c8772f94e79.png?resizew=216)
(1)若平面
平面
.求证:
;
(2)若
,求
与平面
所成的角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4357d5744046d4d44abb09e1ee35fcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2640600496348d6cb642ec0374c28940.png)
![](https://img.xkw.com/dksih/QBM/2021/1/30/2647464178663424/2650174873886720/STEM/22da8196b6d14219a9525c8772f94e79.png?resizew=216)
(1)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c309e58bf083bad13abd549720a63a22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a77e3c1c236141d6118429fade0a9b9d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f4aca5534bce25acaeb7379deed8f8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
解题方法
【推荐3】如图,在
中,
,
是
的中点,
是线段
上的一点,且
,
,将
沿
折起使得二面角
是直二面角.
![](https://img.xkw.com/dksih/QBM/2018/5/1/1935767772651520/1937315098804224/STEM/22751ecbfeb6429cbee800f82259d6eb.png?resizew=246)
![](https://img.xkw.com/dksih/QBM/2018/5/1/1935767772651520/1937315098804224/STEM/85d8cca0c195496ebb13cba73f67f96b.png?resizew=242)
(1)求证:
平面
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adf554b67fc4744960cfe32c0e59a8e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f45265eaed2ba5fc08f6a112a02cd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62eccb33ea66c03222468628f74d8c56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fb241abc97d26f1c693c53acb7c64cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a698deee0d36c8d2772f39247f3f1b03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bde9b5f82a926bc5cc035023d98f3bb0.png)
![](https://img.xkw.com/dksih/QBM/2018/5/1/1935767772651520/1937315098804224/STEM/22751ecbfeb6429cbee800f82259d6eb.png?resizew=246)
![](https://img.xkw.com/dksih/QBM/2018/5/1/1935767772651520/1937315098804224/STEM/85d8cca0c195496ebb13cba73f67f96b.png?resizew=242)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d3f076d3f5a78fc081c252e9a55d5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b38691c0f8804eb03c192070b27fcfee.png)
您最近一年使用:0次