如图,在四棱锥
中,
底面
,底面
为直角梯形,
,
,
,
.点
在棱
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/4d65421b-b777-4d98-af54-5fa42848d367.png?resizew=171)
(1)求证:
平面
;
(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/c45fbffb9e2c7fa7c5006cde8da0cabe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27db558e8db4c957654c8e5cecd2d2dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a120a6e24d8fe8a732940715a22a7a6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/457c2ee2c0139622d2e5de9a51c106b6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/4d65421b-b777-4d98-af54-5fa42848d367.png?resizew=171)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b70cef0b79ca64acbb67dc667fc53b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65277734669566578cbb7d690bb200fb.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79f1787b7a6c0999d4a415616c0b75c3.png)
更新时间:2022-09-28 05:05:30
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,直三棱柱
中,底面边长AB=5,BC=4,AC=3,侧棱长为
,D为BC中点,CE⊥AD,E为垂足.
//平面
;
(2)求证:平面
⊥平面
;
(3)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38387ba1cadfd3dfc4dea4ca9f613cea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5888bec948373f3854258ad80171073d.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5888bec948373f3854258ad80171073d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/475d9dbaac17f65044500bd8fad9a135.png)
(3)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2eb89294b31ffdd2680b4361e8994d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/475d9dbaac17f65044500bd8fad9a135.png)
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解答题-证明题
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适中
(0.65)
【推荐2】如图,直四棱柱ABCD﹣A1B1C1D1中,底面ABCD是∠DAB=60°的菱形,AA1=4,AB=2,点E在棱CC1上,点F是棱C1D1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.
(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/2011/4/16/1570121482297344/1570121485639680/STEM/702333e35a8e4865a4ca06a8961dff10.png?resizew=200)
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解答题-问答题
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适中
(0.65)
【推荐1】如图,已知正三棱锥
的侧面是直角三角形,过
点作
平面
,垂足为
,过
点作
平面
,垂足为
,连接
并延长交
于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/13/65bd94ac-fb86-4e91-86cb-713e8ea5f712.png?resizew=209)
(1)证明:
是线段
的中点;
(2)求平面
与平面
夹角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d2d217e9bcd059908f117dfc4d4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/13/65bd94ac-fb86-4e91-86cb-713e8ea5f712.png?resizew=209)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca48c18021e7be4bbb3e95576e1c1b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
您最近一年使用:0次
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适中
(0.65)
解题方法
【推荐2】如图,四棱锥
的底面四边形
为正方形,
面
,
,
是
的中点.
(1)求三棱锥
的体积;
(2)求平面
与平面
的夹角.
![](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/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a420266b7de21ef35437592cc6028e85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/6/d7b92c9c-8ea0-4231-a62c-4410aaf61d5c.png?resizew=159)
(1)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9bad875ab4b5b8c707d452db4cabaa4.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4d41989d897ddb0fe7aa59f3beaabf9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af68a7bf0da4f7c6f739d2e2461ad9b7.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
【推荐3】如图,直三棱柱
中,
,
,D,E分别是
、
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/9/4680fd59-56ca-4828-b46b-4c6e341288aa.png?resizew=179)
(1)证明:
⊥平面
;
(2)已知
与平面
所成的角为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab917cf28081f6a5e53430bf89cdd8dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10b46ef11527720df2204ed7fca148fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e17230625e72d3a9c6d72ff61019ff61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/488c9cb4d88938d832617f520a3ca951.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/9/4680fd59-56ca-4828-b46b-4c6e341288aa.png?resizew=179)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3f84d1ed2ff6f93bf229c738c58c15c.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/488c9cb4d88938d832617f520a3ca951.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/308b84e8c555534f72247668f2f8ee9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebc8efd06bb73be73feac1046c0fe9bb.png)
您最近一年使用:0次