如图,在三棱锥
中,
是点
在平面ABC上的投影,
,
,
是BD的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/12/c6883d99-9b95-4310-b174-8d75c378b5ed.png?resizew=202)
(1)证明:
平面DAC;
(2)若O点正好落在
的内角平分线上,
,
,
,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4357d5744046d4d44abb09e1ee35fcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c48119b3932497634478f656c752ec4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/12/c6883d99-9b95-4310-b174-8d75c378b5ed.png?resizew=202)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/280247d7df395bb9ea78c51e67b458d2.png)
(2)若O点正好落在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc7ed04c4ea1abe97c7dd2f3e95dc0eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/441a92c002129b752085f041139e2e2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7bae5203f4b4acf23779114b3466e17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41a7841fca64062a1f2112de9e696921.png)
22-23高二·贵州贵阳·阶段练习 查看更多[2]
更新时间:2023-04-11 15:58:49
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相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】棱锥
中,底面
是矩形,
底面
,
是
的中点,已知
,
,
,求:
![](https://img.xkw.com/dksih/QBM/2020/10/15/2571494194323456/2571859572441088/STEM/a02f0bb3374f47a3a0cd0eb94b77a3a0.png?resizew=187)
(1)求证:PA//平面BED;
(2)求异面直线
与
所成的角的大小.
![](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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9c3ec174b1ce835cc8737ff6ce57e52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b80ee363635d73f601654339028daec.png)
![](https://img.xkw.com/dksih/QBM/2020/10/15/2571494194323456/2571859572441088/STEM/a02f0bb3374f47a3a0cd0eb94b77a3a0.png?resizew=187)
(1)求证:PA//平面BED;
(2)求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
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解题方法
【推荐2】如图,在多面体
中,
为正方形,
平面
,
,
.
![](https://img.xkw.com/dksih/QBM/2022/1/14/2894203289747456/2895176848891904/STEM/54939ee7-0352-4531-94f2-2104ea035dd9.png?resizew=196)
(1)求证:
;
(2)求直线
与平面
所成角的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1019c0405370c673e37b46c066eba839.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1100a56e918f75ed6d955a802050f9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c7a63258b68e472bedca08381d47630.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e0346a3f335e7734772d32d9903f2cc.png)
![](https://img.xkw.com/dksih/QBM/2022/1/14/2894203289747456/2895176848891904/STEM/54939ee7-0352-4531-94f2-2104ea035dd9.png?resizew=196)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2187a6bf82f1d5e534274e12f96594be.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3182db896bc2462331796e2a6108363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef00d4825584cf2a3f381de72c179e22.png)
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解答题-问答题
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【推荐1】如图,已知四棱锥
,底面
为边长为2的菱形,
平面
,
,
,
分别是
,
的中点.
;
(2)若
,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/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/304e9d63e7fdc531f4f7b805b765a1b1.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b80ee363635d73f601654339028daec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40df8e474334faad849abb7cc6bbd12c.png)
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(0.65)
名校
【推荐2】如图甲,在梯形
中,
,过点B作
且
,将梯形沿
折叠得到图乙.折叠后
,点F是
的中点.
![](https://img.xkw.com/dksih/QBM/2021/11/4/2844185955991552/2845661538951168/STEM/f3ca2289f91a4a0dbd0fc7c9bc793915.png?resizew=523)
(1)求证:
平面
;
(2)求平面
与平面
所成的锐二面角的余弦值.
![](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/c897a54f2e36bc4b52fba74b41c89d2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f076c2acd240d6e6f83b4b4ca75c839b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7471908a0a105f024773d398576a0f2a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://img.xkw.com/dksih/QBM/2021/11/4/2844185955991552/2845661538951168/STEM/f3ca2289f91a4a0dbd0fc7c9bc793915.png?resizew=523)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c8ccd4181f956f6e0140bf0ab8f0716.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
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适中
(0.65)
【推荐3】如图,已知正方体
的棱长为1,E是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/21/c7ff9c35-9480-4684-9dfd-fd69fa525144.png?resizew=166)
(1)求证:
平面
;
(2)求平面
和底面
夹角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/21/c7ff9c35-9480-4684-9dfd-fd69fa525144.png?resizew=166)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd7cc5d9199856cb62ac8898664c931.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69bcb3226e013650b7d8827c31dd41d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632f2bf1cd0435041fa04b01901d1c8c.png)
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