如图所示,四边形
为菱形.
,
,
,
,
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/3/a47ef5fd-88fd-4f27-8e17-ae81bb47381d.png?resizew=153)
(1)证明:平面
平面
;
(2)若平面
平面
,求实数a的值.
(3)若
,求平面
与平面
所成二面角的正弦值.
![](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/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69b7af35a4b337ee57859c186abc0c2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/277ad9925f187b4bd4e79e9a2c611c82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1e0bd4b30dc777ac9da80f6baa3eb31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/3/a47ef5fd-88fd-4f27-8e17-ae81bb47381d.png?resizew=153)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39282bdf319f30d7bc261e2e3ab3b1e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6501f1c913a4ef64957a2f01ab5baa15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6261790c66cc71ee3898afabad0c09f4.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8120119749d4bc28067e73fca7d46cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
更新时间:2020-10-03 20:12:41
|
相似题推荐
【推荐1】如图,将一副三角板拼接,使它们有公共边BC,且使两个三角形所在的平面互相垂直,若
∠BAC=90°,AB=AC,∠CBD=90°,∠BDC=60°,BC=6.
![](https://img.xkw.com/dksih/QBM/2018/7/17/1990443664089088/1991739199471616/STEM/9c6799196cef4155a4302f9755b60d41.png?resizew=156)
⑴ 求证:平面
平面ACD;
⑵ 求二面角
的平面角的正切值;
⑶ 设过直线AD且与BC平行的平面为
,求点B到平面
的距离.
∠BAC=90°,AB=AC,∠CBD=90°,∠BDC=60°,BC=6.
![](https://img.xkw.com/dksih/QBM/2018/7/17/1990443664089088/1991739199471616/STEM/9c6799196cef4155a4302f9755b60d41.png?resizew=156)
⑴ 求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcf6dc837ae85207789b94d109c5c2eb.png)
⑵ 求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca6d1c5eace748465b2dad5065f5111c.png)
⑶ 设过直线AD且与BC平行的平面为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
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解答题-证明题
|
适中
(0.65)
【推荐2】如图,四边形
为正方形,
分别为
的中点,以
为折痕把
折起,使点
到达点
的位置,且
.
(1)证明:平面
平面
;
(2)求
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fa7d487586e3702f55cd2d6466654bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0da385619932723a92ba12567c97137c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffb9820cccc66e71103238c86934696a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce1132157a33c82610c2d5035493d024.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fc5c19ac440746be97d8b46af5d288a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d80c77074f338f16b1a973626f9bf7dc.png)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/545b3e55e1c6898cada0ed88786d5f22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85719346f464a101d365d42be27450a3.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fd17a66a2af938c89e46f22e4d893b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85719346f464a101d365d42be27450a3.png)
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解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】在三棱台DEF−ABC中,CF⊥平面ABC,AB⊥BC,且AB=BC=2EF,M是AC的中点,P是CF上一点,且CF=
DF=
CP(
).
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/14/8001e500-28bf-45c0-aa05-582c28d4745d.png?resizew=185)
(1)求证:平面BCD⊥平面PBM;
(2)当CP=1,且二面角E−BD−C的余弦值为
时,求三棱台DEF−ABC的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7043c5176a2673360277467c88198e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76d8047f0a8bd0cf4e250cd0fe80093b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/14/8001e500-28bf-45c0-aa05-582c28d4745d.png?resizew=185)
(1)求证:平面BCD⊥平面PBM;
(2)当CP=1,且二面角E−BD−C的余弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3ffd5c35bba71ea54c28622b6cf505d.png)
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解答题-问答题
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适中
(0.65)
名校
解题方法
【推荐2】如图1,平面图形
由直角梯形
和
拼接而成,其中
,
,
,
,
,
与
相交于点
,现沿着
将其折成四棱锥
(如图2).
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/3/f03ecb76-bf45-49f7-a6df-cea747e7ddb8.png?resizew=300)
(1)当侧面
底面
时,求点
到平面
的距离;
(2)在(1)的条件下,线段
上是否存在一点
,使得二面角
的余弦值为
?若存在,求出
的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea1e3a43d0fa18f6c0888ba804d5b329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80d69d26240b1b89b0791a563aab964a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/829018a6ca0aff95d89e3f7cd943274e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d730ae4307db56b47849c3a19dedfb3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1328e05d150f86dbe18656662eaa8f6b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0453cfd7e92bf7746a88280b9e7b580.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/3/f03ecb76-bf45-49f7-a6df-cea747e7ddb8.png?resizew=300)
(1)当侧面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)在(1)的条件下,线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f8b47a0a7c3029a7c7ed3ed5b4993fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1174142f3bba761585b6bc2653009b36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff82dc4f9daf2658ee50f550ffdeac58.png)
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解答题-问答题
|
适中
(0.65)
【推荐3】如图,在三棱锥
中,平面
平面BCD,
,O为BD的中点.
(1)证明:
;
(2)若
是边长为1的等边三角形,点E在棱AD上,
,且二面角
的大小为45°,求直线AC与平面BCE所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcf6dc837ae85207789b94d109c5c2eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e735a28578ba191da6d4f3b0f8e8729.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/28/29667b56-38eb-440f-8f14-31fbae7c9998.png?resizew=168)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21be01a95cdd3149512bf95d6084fdd6.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4807ca16360c0cca436e59d4be98f626.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46d76c5ac5c9f0a2ec064487c02c476e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/324d453870b345da0c41977290192f94.png)
您最近一年使用:0次