三棱锥被平行于底面
的平面所截得的几何体如图所示,截面为
,
,
平面
,
,
,
,
,
.
(1)证明:平面
平面
;
(2)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99b16cff607cdc2d69afc70dc778acbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f8e9ec412ea0355e4e5cd06c60e5fee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ecf072589c0f901d92f6bda111d841.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08c596aff6331566a0149449183c2024.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21ea52361458ce2e49ed0fe99d8e6c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb5b12692517a39c320f99a479eb055.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9260ee90b4107dcdc5b2b0937c40e8c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0870515b612ef842f01f3b5eeca220b5.png)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daae7d7d44e425de626f1081f682aa56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa84da7ead562cffd02afd5940f8aa3.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688032870400/1569688174141440/STEM/b6e5477cdd4b4a1ca9514d11c276bb44.png?resizew=244)
更新时间:2016-11-30 03:21:40
|
相似题推荐
解答题-证明题
|
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(0.85)
名校
解题方法
【推荐1】如图,在正方体
中,
,
分别是
,
的中点.
(1)求证:
平面
;
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.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/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7dfd4c4648dc52d0952c20f3978fadd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/4/a9666486-1981-477c-82af-1efa5c8f00b0.png?resizew=160)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c08e30d164e122bbbdf42162fbb5ceb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661df691bacf67f20557fef29c1af1eb.png)
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解题方法
【推荐2】如图,正方体中,E、F分别是
、
上的点,并且
.求证:B、E、
、F共面.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bac8911246624118ff506edd4eb14e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6795cae2df43a722e1355e9562d93c09.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/9/7fb667eb-b6e3-4722-8270-b6947fec3f72.png?resizew=156)
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解答题-证明题
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名校
【推荐1】如图,四棱锥
的底面是矩形,
底面
,
,
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/6/8e56b71a-0e90-4761-80a0-281d80c716bb.png?resizew=140)
(1)求证:
平面
;
(2)求平面
与平面
所成的角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffddeafce03aae663bc823e2d5127c61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/6/8e56b71a-0e90-4761-80a0-281d80c716bb.png?resizew=140)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a5edfe97aeab0cf16b40fa9d2e15f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c745df4f226027778d5fe45b6501b822.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
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【推荐2】已知四棱台
,下底面
为正方形,
,
,侧棱
平面
,且
为CD中点.
平面
;
(2)求平面
与平面
所成角的余弦值;
(3)求
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f54638dd4ebf19815a1333d84e42f927.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8889b0d606a02a661f3d071fa672d83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d850305485a6d3ee30fe313dc8bb736.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/679748eab882a6be0fefd2cc300349a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
(3)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/679748eab882a6be0fefd2cc300349a4.png)
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解答题-问答题
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(0.85)
【推荐3】如图,长方体
中,
,
,点
在
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/ad5ae77a-79e7-451c-8c73-b570086c2b8b.png?resizew=160)
(1)证明
⊥平面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e55a2310cbba5e050488cd9296eb195d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27db558e8db4c957654c8e5cecd2d2dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53e97fcdcfd6183b976a61ef3222c607.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/065f2c3527fcc9d84939c47ac8640643.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/ad5ae77a-79e7-451c-8c73-b570086c2b8b.png?resizew=160)
(1)证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/926584088b939200d88e64318f2d4e6c.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/628d6fc46c651e0c783b81a123a7b229.png)
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