如图,ABCD是平行四边形,
平面ABCD,
,
,
,
,F,G,H分别为PB,EB,PC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/c57cd1b7-e140-43a5-9584-9e8acdd45f29.png?resizew=244)
(1)求证:
;
(2)求平面FGH与平面EBC所成锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed04b01505bbd8a4ac0bc12e46f23bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae11df2c6b8f8ca221c79851d19f6f88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f40cf9b89adc1e18924326f7de66b0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f08273d339dc5ddbb89aa67bb8205e6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/c57cd1b7-e140-43a5-9584-9e8acdd45f29.png?resizew=244)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7af6b64dde5e04b831b761fa0b3e08db.png)
(2)求平面FGH与平面EBC所成锐二面角的余弦值.
更新时间:2019-11-23 23:02:09
|
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,已知三棱柱
中,
,四边形
是菱形.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/5/8b4c74f9-0e65-41a5-b7cd-4f2c1288abd4.png?resizew=199)
(1)求证:
平面
;
(2)若
,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82f66db529e2225cfad120ac0a16e8a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/5/8b4c74f9-0e65-41a5-b7cd-4f2c1288abd4.png?resizew=199)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e89195bacd53d43195e70c12b5cfa041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea848cd2aa3a464618020475097949fc.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3eaf495d848878fcf77e75cc590ee2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/659c9097649d5c2a0082a5ce83a7e4d7.png)
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【推荐2】如图,四棱锥
中,
平面
,
,
.
,
,
,
是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/564d2302-0db8-4489-8ec3-be883425e3bc.png?resizew=157)
(Ⅰ)证明:
⊥平面
;
(Ⅱ)若二面角
的余弦值是
,求
的值;
(Ⅲ)若
,在线段
上是否存在一点
,使得
⊥
. 若存在,确定
点的位置;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a4d781525777c7b5284dffc70b2a28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0da2ebc3c7d1de745f52ae6908bebf3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81f17680a23635f823b7dc446e4f3b0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83a04565a8ebaa111894b724b0ba266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e0c26071fa1ebab92b8e750fd50d828.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/564d2302-0db8-4489-8ec3-be883425e3bc.png?resizew=157)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(Ⅱ)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbeab80976db9b4689b9446cda06196a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/827ccf0c04aa941ba20d5f4c6068b46b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
(Ⅲ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e94f16d5ed858699bfea5039a7bf8ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fb26d84907c923278ac4626a9d58947.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
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解答题-问答题
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适中
(0.65)
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解题方法
【推荐1】如图,
,
,
平面
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/9290f510-3471-4ee0-ae48-8e5f3532a81f.png?resizew=149)
(1)证明:
;
(2)求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bda4219d44f7529748a47958b38cfee5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5029873381d4d3caa26ab0ba54d816ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44c4ad115032afd6e0fa71d88d962c08.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29e5a6afab22d5b53c1d8e87d58e8020.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/9290f510-3471-4ee0-ae48-8e5f3532a81f.png?resizew=149)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fa8345302e8036af33d4598282144d7.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b18e51cdf630481de16dc93bcd8591f.png)
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【推荐2】四棱锥
中,底面
是菱形,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/f2a0d766-8800-49e1-8be3-df2e56ee40a2.png?resizew=178)
(1)求证:
;
(2)若
是
的中点,求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d02bd5cfe804460846423e77f72db10f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bbc0ed0e0ecd2f662b26f11d937ae29.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/f2a0d766-8800-49e1-8be3-df2e56ee40a2.png?resizew=178)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee261dd8ea7475c901d21f7c71ba025a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1870606080b360249be4d935c64b4710.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3182db896bc2462331796e2a6108363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7609a1407f1e965fc9f1235552dcf9e.png)
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【推荐1】如图所示,在四棱锥S-ABCD中,SA⊥平面ABCD,底面ABCD是梯形,AB//CD,DA⊥AB,BC⊥SC,SA=AD=3,AB=6,点E在棱SD上,且VS-ACE=2VE-ACD.
![](https://img.xkw.com/dksih/QBM/2018/12/12/2095288687992832/2096500801265664/STEM/b674c715882945e29eefdf4fea210a50.png?resizew=181)
(1)求证:BC⊥平面SAC;
(2)求二面角S-AE-C的余弦值.
![](https://img.xkw.com/dksih/QBM/2018/12/12/2095288687992832/2096500801265664/STEM/b674c715882945e29eefdf4fea210a50.png?resizew=181)
(1)求证:BC⊥平面SAC;
(2)求二面角S-AE-C的余弦值.
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【推荐2】如图所示的几何体中,底面ABCD为直角梯形,
,
,四边形PDCE为矩形,平面
平面ABCD,F为PA的中点,N为PC与DE的交点,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/1/2424014c-8d14-426c-8a28-9caffd3b5f29.png?resizew=202)
(1)求证:
平面
;
(2)若G是线段CD上一点,平面PBC与平面EFG所成角的余弦值为
,求DG的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6379891c7150af4188b5ab746d703bae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbe7a201432af0a2f9d21c6803906f5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0046177466c78f08d45449dc5639bf38.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/1/2424014c-8d14-426c-8a28-9caffd3b5f29.png?resizew=202)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d53d5c96de34fcf95794e51c2761b671.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)若G是线段CD上一点,平面PBC与平面EFG所成角的余弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64f1145c162038df3c7184d9201c628e.png)
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【推荐3】如图,已知三棱柱
中,
与
是全等的等边三角形.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/16/f36fe622-736c-4b1a-a033-65bf26fccf6f.png?resizew=195)
(1)求证:
;
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f2533329cee82bcfe15b808839c0a02.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/16/f36fe622-736c-4b1a-a033-65bf26fccf6f.png?resizew=195)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7768503b1ad4775258b2f1a71c413086.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d24a13d7a9e243b7227f7802ce9a7390.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26935a004b64ae14d81d9b82c8d31e2f.png)
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