如图,已知平行四边形
中,
,
,E为边
的中点,将
沿直线
翻折成
.若M为线段
的中点.
![](https://img.xkw.com/dksih/QBM/2020/8/20/2532077616037888/2541733831622656/STEM/0877bc3d-89a0-4143-8df4-3f745d8e0ac9.png?resizew=534)
(1)证明
平面
,并求
的长;
(2)在翻折过程中,求三棱锥
的体积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abc28e69c1ba0aac981256887f7dfa94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3aa2a83fed9bf4cb09d84a980452e346.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://img.xkw.com/dksih/QBM/2020/8/20/2532077616037888/2541733831622656/STEM/0877bc3d-89a0-4143-8df4-3f745d8e0ac9.png?resizew=534)
(1)证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8c70966a318ef8ecf874257f5c5e5db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/657dffbd3623b705f871878fbd9df57e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e5c62f22d7afc5627fcb86599faa8e1.png)
(2)在翻折过程中,求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53d5cf6415cc66f3617f330f28ae09fe.png)
更新时间:2020-09-03 11:53:37
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,直角
中,
,
,D,E分别是AB,BC边的中点,沿DE将
折起至
,且
.
![](https://img.xkw.com/dksih/QBM/2020/3/7/2414498511429632/2416041010561024/STEM/f4eef41bdc2e489ebc9c0e644e4c13ed.png?resizew=209)
(1)求四棱锥
的体积;
(2)求证:平面
平面ACF.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a355958abf7dc0f2eb949584cb87907b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29186a13b95f9972102e10cbbce70e81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15514bc735fe4b744672edefe00009c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc7f32e4c7d1fcafc3fe0dbcf08fdd2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5286e4c78138ede27895ce2bfe9b6b34.png)
![](https://img.xkw.com/dksih/QBM/2020/3/7/2414498511429632/2416041010561024/STEM/f4eef41bdc2e489ebc9c0e644e4c13ed.png?resizew=209)
(1)求四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7a182050ea82f1778d508d461ad4f23.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d62d30d732c3c6ee3f0dd66d7059356.png)
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适中
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解题方法
【推荐2】如图,四棱锥
中,
底面
,
,
,
,
,
是
上一点,且
,
是
中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/28/0c78def8-65c4-4e08-bbaa-bf6b5b019b5e.png?resizew=140)
(1)求证:
;
(2)若二面角
大小为
,求棱锥
的体积.
![](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/7bb5b12692517a39c320f99a479eb055.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e921f46d90e43f4517c55832b6280f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fcc9a4a6d0ad203358b16760fadc2d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84d81d732204a3c2384a27606f858677.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c0b9ae1fdf6b88a97ff8d01c0ecdaa0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/28/0c78def8-65c4-4e08-bbaa-bf6b5b019b5e.png?resizew=140)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4125524caac016727c80d2722c5ba3.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b796bbaeb8450404c2d146283562006e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1e5fa72f2878b476bc57f0df12d6555.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2f4aef2d294ce066c517691155cbb78.png)
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解答题-证明题
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适中
(0.65)
【推荐1】如图,已知点
是正方形
所在平面外一点,
平面
,
,
、
、
分别是
、
、
的中点.
(1)求证:
平面
;
(2)求证:直线
平面
;
(3)求直线
与平面
所成的角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.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/ced3d3dd6af84fb052fc7281d707853e.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/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/17/06b06484-08b8-415b-bf79-1e36d0ad0e80.png?resizew=156)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7592c4f01c8e06c7ee90df5b9413a9f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14ddcfd8985d6ef923063a301e2bc5ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(3)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
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适中
(0.65)
名校
【推荐2】如图所示,在几何体ABCDEF中,四边形ABCD为直角梯形,AD∥BC,AB⊥AD,AE⊥底面ABCD,AE∥CF,AD=3,AB=BC=AE=2,CF=1.
![](https://img.xkw.com/dksih/QBM/2022/5/30/2990327739441152/2990678540328960/STEM/81d86ab2-3111-46cf-b338-e0a73cc0d9bb.png?resizew=208)
(1)求证:BF∥平面ADE;
(2)求直线BE与直线DF所成角的余弦值;
(3)求点D到直线BF的距离.
![](https://img.xkw.com/dksih/QBM/2022/5/30/2990327739441152/2990678540328960/STEM/81d86ab2-3111-46cf-b338-e0a73cc0d9bb.png?resizew=208)
(1)求证:BF∥平面ADE;
(2)求直线BE与直线DF所成角的余弦值;
(3)求点D到直线BF的距离.
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