在四棱锥
中,
平面
,
,
,
,
为
的中点,在平面
内作
于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/7e900cbb-39f4-4989-82b0-22eefa368f53.png?resizew=190)
(1)求证:平面
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/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f5019d74a9497f861a0f755ea31d010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f028aa2f87b30aec1d9070c30c305f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a1cacb8d68bac8bca9a950b9dd02819.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/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b7b9bf7332256ac478041957fa2a55a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/7e900cbb-39f4-4989-82b0-22eefa368f53.png?resizew=190)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6501f1c913a4ef64957a2f01ab5baa15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5102c216393e133fa25dba98cd78535.png)
2019·新疆克拉玛依·三模 查看更多[2]
更新时间:2021-11-11 22:15:22
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在四棱锥
中,
面
,且
,
是
的中点,求证:面
面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.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/36528bb50bf0d984ed1f5119700b4834.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/342d452a7b850cd3a15b23619ad39bd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e6c2dad46a9052a4185a4f7b4ae8a2e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/22/cd723bee-f9c7-48ba-9716-6e6d744ea002.png?resizew=159)
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2】如图,在四棱锥
中,底面
为直角梯形,
,
,
,
,
是
的中点,
是棱
上的点,且
.
(1)求证:平面
底面
;
(2)求二面角
的大小.
![](https://img.xkw.com/dksih/QBM/2016/5/5/1572620670140416/1572620676153344/STEM/fd00d0f79ec3448586c640030f95e2e4.png?resizew=198)
![](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/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4795ee1f96b430529934e2231b38885d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29ec1d702ce59463c2a1fc468f3da5e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49d018f0f1a40a5e20179f42c1722946.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1b79bf9d502660aff58cec76863e610.png)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a773fe6d12311dc321198697eb528ba.png)
![](https://img.xkw.com/dksih/QBM/2016/5/5/1572620670140416/1572620676153344/STEM/fd00d0f79ec3448586c640030f95e2e4.png?resizew=198)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】如图,在平面四边形
中,
为边长为2的正三角形,
,点
为
的中点,沿
将
折起得到四棱锥
,且
.
(1)证明:
;
(2)点
为线段
上的动点(不含端点),当平面
与平面
的夹角为
时,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d8a4ce7401077d7ccb990813bd88bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40560ea08d6cd8c1d4d9661ee6faaa3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71b63d2504bd3ecce8c10560b142356f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/372629a8666de1e9bac3e7daadcac7b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b744576b325f894cc71ffa1aa4d38b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e1b638760d907efe836500581da1596.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/10/892dd4a0-aa54-467d-b381-1045a3bae1d4.png?resizew=355)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5d56d8170b764b80a672cd6c861921.png)
(2)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15b63176f43bc7a0654d0f6f45e7429.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65277734669566578cbb7d690bb200fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ac09dc1ca2cdd7aef28c218763d3e4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bcba2bdb3f754888dfde4bd56969046.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】四棱锥
中,
平面
, 底面
是 等腰梯形, 且
, 点
在棱
上.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/ccb09c21-ea2a-4341-ac26-d88f29819c1d.png?resizew=143)
(1)当
是棱
的中点时, 求证:
平面
;
(2)当直线
与平面
所成角
最大时, 求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5f1897a7e856b42f8cee0f286ad913d.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/2045a73e0dea1d483373c5a8b858e7e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/457d407ca96640f77ef995963c26ce93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/ccb09c21-ea2a-4341-ac26-d88f29819c1d.png?resizew=143)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/457d407ca96640f77ef995963c26ce93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5865d488a9cf1181016fd2e866177cdd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)当直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5fb9fdf59fd12b2ae88824bc557938.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/167e4b949f6bda469c5ac4af5a85a0db.png)
您最近一年使用:0次