如图,在水平放置的四棱锥
中,
平面
,
,
,
.
![](https://img.xkw.com/dksih/QBM/2021/4/28/2709693311049728/2798224034095104/STEM/8d64896f-9f13-4a2b-868b-ea61b5d2bc2b.png?resizew=217)
(1)
为线段
上动点,试确定点
的位置,使
并证明;
(2)求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc655b4d76a5b4d74271082ced237657.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e04a28a7f47d499eaf7451d5a6c3872.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b9d54cbbf601f4583659771eb534997.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8372da7e78999d2016ce485fba43ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf410aab32ba002b2c4e7343e7efd4c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d81ddfbd5549f312ade47cb7f740059.png)
![](https://img.xkw.com/dksih/QBM/2021/4/28/2709693311049728/2798224034095104/STEM/8d64896f-9f13-4a2b-868b-ea61b5d2bc2b.png?resizew=217)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dee2d6f5c8afb4081176d398a8f0469.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11c3762eb09409441a1d1d7c0ccbbe60.png)
更新时间:2021-08-31 21:04:16
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,
的底面边长为2,高为
的正三棱柱,经过
的截面与上底面相交于
,设
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/24/7dfa21be-cfff-411d-8b54-c752119e9e46.png?resizew=170)
(1)证明:
;
(2)当
时,在图中作出点
在平面
内的正投影
(说明作法及理由),并求四棱锥
表面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/860884c0017c8bceb5b0edff796c144f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3dcfd0bf7e6fd58dba0404f1300d356b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/24/7dfa21be-cfff-411d-8b54-c752119e9e46.png?resizew=170)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dcc81f1bf10ddf0cd30c0ababaf2874.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73b3cf0f585938ede9eca890a6eb326d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe83f1ae7e5f05d8bed6bf6f42db0e7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/858f284c387da8f005621953a381462b.png)
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解答题-证明题
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名校
【推荐2】在三棱锥
中,
底面
为
的中点,
为
的中点,点
在
上,且
.
(1)求证:
平面
;
(2)求证:
平面
;
(3)若
,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c45fbffb9e2c7fa7c5006cde8da0cabe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c0784c8f32a386cab2a13148c6e72aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a41ada2c69a8c4ff1c0a9c780d2a08d.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56fdf217165748fafe938b64fa08179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5865d488a9cf1181016fd2e866177cdd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87c0bfeadcf17b2a45896071f07a4a5a.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b97aa0d985b33b0d82571b0b3a383e6c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51f73a0ca4e6c794242489066fddb6c5.png)
![](https://img.xkw.com/dksih/QBM/2017/10/3/1787390111784960/1787465234677760/STEM/f0c9b4fefa994caea80d432713bbfc72.png?resizew=193)
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解题方法
【推荐1】如图,四边形ABCD是棱长为2的正方形,E为AD的中点,以CE为折痕把△DEC折起,使点D到达点P的位置,且点P的射影O落在线段AC上.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/b26d11de-9987-4327-acc0-a18acb51c84a.png?resizew=193)
(1)求
;
(2)求几何体P﹣ABCE的体积.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/b26d11de-9987-4327-acc0-a18acb51c84a.png?resizew=193)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f17ad922989275719327666ab39985d1.png)
(2)求几何体P﹣ABCE的体积.
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解答题-作图题
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适中
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名校
解题方法
【推荐2】在棱长为
的正方体
中,
分别是
的中点,过
三点的平面与正方体的下底面相交于直线
;
(1)画出直线
;
(2)设
,求
的长;
(3)求
到
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6670479a0083dd2dfd5ad55b47b1ab6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2403734bfa7f845afaf883213548656.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80bbe13f5c674ba211bc31948cc91151.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/20/773bd718-81f0-4a60-9036-136944228309.png?resizew=169)
(1)画出直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3205333c4db3a336a8351de593266351.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24006d28116bc097933cc90bcc0ea69f.png)
(3)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】在如图所示的几何体中,
平面
,
平面
,
,
,
是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/28/0370cf55-b102-4527-bb65-8323f4096abd.png?resizew=147)
(1)求证:
;
(2)求
与平面
所成角的大小;
(3)求平面
与平面
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/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4c5ae16a7145a28a91d45ef950a07c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/615fc8790237a1b09af51d6bcad6b595.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0134a8463eec67424af096f369777557.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/28/0370cf55-b102-4527-bb65-8323f4096abd.png?resizew=147)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/785546906851d56da452b46052eeb8a0.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/383ec3453527947ed7a5960e9a8fbe0b.png)
(3)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10fc7991ea17d54ff5f4445ac5699463.png)
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解答题-证明题
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【推荐2】如图,已知在直四棱柱
中,
,
,
.
![](https://img.xkw.com/dksih/QBM/2011/3/28/1570067445104640/1570067450396672/STEM/e8146c1c-7cb7-4c54-8ba9-70b5c698b71f.png?resizew=259)
(1)求证:
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/4a0e5697eca3f5205cb7b343648240bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd8e727e4efc22b49649f71ae9c9d84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/280011846e091743c4fc6b6ed1c698f4.png)
![](https://img.xkw.com/dksih/QBM/2011/3/28/1570067445104640/1570067450396672/STEM/e8146c1c-7cb7-4c54-8ba9-70b5c698b71f.png?resizew=259)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4c5ae16a7145a28a91d45ef950a07c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f96c673a2381f118ea2d3efc0bca1f3.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98e0254c84e44728749b34c08c28ab1e.png)
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【推荐3】如图1,在矩形
中,
,
,将
沿矩形的对角线
进行翻折,得到如图2所示的三棱锥
.
时,求
的长;
(2)当平面
平面
时,求平面
和平面
的夹角的余弦值.
![](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/1ffc2817fa590affb5a760a25dc65308.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a77e3c1c236141d6118429fade0a9b9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
(2)当平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcf6dc837ae85207789b94d109c5c2eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
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