如图,EB垂直于菱形ABCD所在平面,且EB=BC=2,∠BAD=60°,点G、H分别为线段CD、DA的中点,M为BE上的动点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/f4134a83-f2d8-48a2-a19a-b58415b15228.png?resizew=206)
(Ⅰ)求证:GH⊥DM;
(Ⅱ)当三棱锥D﹣MGH的体积最大时,求三角形MGH的面积.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/f4134a83-f2d8-48a2-a19a-b58415b15228.png?resizew=206)
(Ⅰ)求证:GH⊥DM;
(Ⅱ)当三棱锥D﹣MGH的体积最大时,求三角形MGH的面积.
更新时间:2020-03-16 19:01:34
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相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,
为正三角形,
平面
,
,
为
的中点,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/19/61189463-dbbe-4a8d-89b3-8ca500bf712e.png?resizew=141)
(Ⅰ)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
平面
;
(Ⅱ)求多面体
的体积..
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f09ad78d4eccd1a9c9ccd3c4af79c79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/082f4777d26f09734bfa559e064038fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1642eec556eb252de9c1ab7bb5ca90b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afc09970c72e7921f392bdac2b51fcce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfb08f6a798dc293f3d8de281190f65e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/19/61189463-dbbe-4a8d-89b3-8ca500bf712e.png?resizew=141)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(Ⅱ)求多面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c72241c1869dbb03756e031d4ab1a713.png)
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解答题-问答题
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适中
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名校
【推荐2】如图,在直角梯形
,
,
,
,点
是
的中点,现沿
将平面
折起,设
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/c8695aa0-5acc-4bec-8633-02089829efe8.png?resizew=319)
(1)当
为直角时,求直线
与平面
所成角的大小;
(2)当
为多少时,三棱锥
的体积为
;
(3)在(2)的条件下,求此时二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4864c21e9664fa9111ede6425b09563a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab37d59a157987d018576c31f2c626ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e51b89f545616ef48f3706850107ad95.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bb47295ebe8c29208b0d52407de0334.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/513cb0e220a0fed33454151e303bcbe7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/c8695aa0-5acc-4bec-8633-02089829efe8.png?resizew=319)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddfe0ccf24d760c77535a70c92dad145.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69a8b76e36783a69d14ec54af82c7df0.png)
(3)在(2)的条件下,求此时二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4294b7141d394654841008ac9b40dab.png)
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解答题-证明题
|
适中
(0.65)
【推荐1】如图,菱形
的边长为
,对角线
,现将菱形
沿对角线
折叠至
,使
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/669774e5-30fc-4c05-a49c-90f88dc0b107.png?resizew=360)
(1)求证:
;
(2)求二面角
平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e1f4f255d191786f7d330d278868c2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3953cec61ac602ce5eb59b7912352179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7afa7298635295e537ef588224c965b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/669774e5-30fc-4c05-a49c-90f88dc0b107.png?resizew=360)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5246843f1a889aa46674bfe3a404c184.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d331cfebfcd0ed6280b2e54fb059e14c.png)
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】如图,在四棱锥
中,
平面
,
,
,
,
,点
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/74e809b5-53d8-4762-a010-7344c3f56aee.png?resizew=150)
(1)证明:
.
(2)求点
到平面
的距离.
![](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/e2ced8225ff27c8e3e1897b8629312d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/077c956ac0eb05cf120e14f17413dfa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d5ba108d7d2d4807f2c74a22e536fe9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d47dff1b9d37e2b2cb2afe4bd0c4c04f.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/2022/11/25/74e809b5-53d8-4762-a010-7344c3f56aee.png?resizew=150)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4398a409532d9a2a7504f91c5be1b93.png)
(2)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
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