如图四棱锥
中,底面
是正方形,
平面
,且
,
为
中点,
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/26/b9e2f6aa-ff0f-4ea8-8746-d5d884b74ee3.png?resizew=165)
(1)求证:
平面
;
(2)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/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83a04565a8ebaa111894b724b0ba266.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/2022/10/26/b9e2f6aa-ff0f-4ea8-8746-d5d884b74ee3.png?resizew=165)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffc3380658a60e5c139bc30572e0e98c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06ffd37dac71a9caeb51b932606e308a.png)
更新时间:2020-01-12 12:59:13
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,在直三棱柱
中,
,
,
,
,点
是
的中点.
![](https://img.xkw.com/dksih/QBM/2020/10/20/2575047803912192/2577886581202944/STEM/d96f7f59b95b4a73b9d138a83306e3d2.png?resizew=180)
(1)求几何体
的体积
(2)求证:
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d70dc2c20619a4fc12a0cfda59af5b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65a3e478bb87d094e3a0af30dd10ae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f08273d339dc5ddbb89aa67bb8205e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e55a2310cbba5e050488cd9296eb195d.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/2020/10/20/2575047803912192/2577886581202944/STEM/d96f7f59b95b4a73b9d138a83306e3d2.png?resizew=180)
(1)求几何体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b147cfec760e23e61a531609cef9a96f.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4557a368725226f2c8ea2efb7d30e478.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbc7e774e4ae40c23bf4ceed179230ca.png)
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解答题-问答题
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适中
(0.65)
名校
【推荐2】已知三棱柱
的侧棱垂直于底面,
,
,
,
,
分别是
,
的中点.
![](https://img.xkw.com/dksih/QBM/2018/7/4/1981271614906368/1981995012349952/STEM/4c734e040c9c49f7803da7ca127ec70f.png?resizew=227)
(Ⅰ)证明:
平面
;
(Ⅱ)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92105835f8075cb75dff244e908370b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca036d049f5205cf04cb1b9c5cd03f97.png)
![](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/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/2018/7/4/1981271614906368/1981995012349952/STEM/4c734e040c9c49f7803da7ca127ec70f.png?resizew=227)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcf19a7f0dd0cdf59516ae585025110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bb4bf20b186fdaae7736a1d99a7f919.png)
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解答题-问答题
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适中
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【推荐1】如图,直三棱柱
中,
是棱
的中点,棱
上的点
满足
,棱
上的点
满足
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/10/80e1d878-1974-4543-85ef-a1eb4ed8d233.png?resizew=213)
(1)证明:
;
(2)若
与平面
所成的角为
,求平面
与平面
所成锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d950edc44a7d2e4828752a70a0d6fc3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](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/93bc4c9dd737193f7acce692b23500d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06fa0a286a55692e4263a5993b01580b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/10/80e1d878-1974-4543-85ef-a1eb4ed8d233.png?resizew=213)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/385d9b0855d5d459dbec1a6bb00c6f21.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d5bca00fa20e6e80480b9d06d2e52ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68cc7dc4e1e3c7ec5ecda50a696eb50a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85709fa76f316e9f0b13ac297f3814c0.png)
您最近一年使用:0次
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适中
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【推荐2】如图,在直三棱柱
中,点
是
中点,点
是
的中点,连接
.
(1)证明:
平面
;
(2)若
,
,
,求二面角
的余弦值的大小.
![](https://img.xkw.com/dksih/QBM/2013/10/22/1571374224465920/1571374230339584/STEM/e7468bc7e08544c99a1670f01b502503.png?resizew=305)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7592c4f01c8e06c7ee90df5b9413a9f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/126a3d8d69d4623cefbd444020e92db5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0218542daefa15910d5111b27e71f5b3.png)
![](https://img.xkw.com/dksih/QBM/2013/10/22/1571374224465920/1571374230339584/STEM/e7468bc7e08544c99a1670f01b502503.png?resizew=305)
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【推荐3】如图所示,已知矩形ABCD和矩形ADEF所在的平面互相垂直,
,M,N分别是对角线BD,AE上异于端点的动点,且
.
![](https://img.xkw.com/dksih/QBM/2022/6/2/2992554288586752/2994315921702912/STEM/28350c27-c49c-47a6-8551-13d0adc834bc.png?resizew=200)
(1)求证:直线
平面CDE;
(2)当MN的长最小时,求二面角A-MN-D的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34e92ffeacd9cc1f339fcf263468fd2a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c30fad9d4f86033bcd8375ddd6d3874.png)
![](https://img.xkw.com/dksih/QBM/2022/6/2/2992554288586752/2994315921702912/STEM/28350c27-c49c-47a6-8551-13d0adc834bc.png?resizew=200)
(1)求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1eaa5e336f830a3e5cd60ff7a756f3ef.png)
(2)当MN的长最小时,求二面角A-MN-D的正弦值.
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