如图所示,在四棱柱
中,底面
是梯形,
,侧面
为菱形,
.
![](https://img.xkw.com/dksih/QBM/2020/8/10/2524927743574016/2527670660644864/STEM/5926af6ed9bc45b29d5195509423c3c6.png?resizew=425)
(1)求证:
;
(2)若
,点D在平面
上的射影恰为线段
的中点,求平面
与平面
所成锐二面角的余弦值.
![](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/34e0a957a55460c72673c0f2ee90dbb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae5a19e74dfd34b87b2f3e4d16c583cb.png)
![](https://img.xkw.com/dksih/QBM/2020/8/10/2524927743574016/2527670660644864/STEM/5926af6ed9bc45b29d5195509423c3c6.png?resizew=425)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5b0bfe1e7a956345f7ed58a3b2faa70.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d11340b4efe070df4a9f00744fa8f310.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b54387f870ae37f7951b253665d64f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
更新时间:2020-08-14 15:02:02
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】在三棱锥
中,平面
平面
是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/25/75f6049e-eb40-4229-922c-9591f885510e.png?resizew=140)
(1)证明:
;
(2)若
,求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ceb6d5778a6349ce60f273c1af56b82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f829f73b6c3924d17eb78fa414d34d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af96f607b8d9b0b22a373865d2f6c9e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/25/75f6049e-eb40-4229-922c-9591f885510e.png?resizew=140)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee730f6a2551fb1b582ecf290cfea233.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fa950380fd3c95d0782d09d7ac3ee16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36fb434ccf8340815b6e2cadc74b2f09.png)
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【推荐2】如图所示,在三棱柱
中,底面
为正三角形,
在底面
上的射影是棱
的中点
,
于
点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/6/e33f501d-d410-4edf-bec9-c4202439b2eb.png?resizew=214)
(1)证明
平面
;
(2)若
,求
与平面
所成角的正弦值.
![](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/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c29b6be34c91a2d5fb314c8a2d9a1660.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/6/e33f501d-d410-4edf-bec9-c4202439b2eb.png?resizew=214)
(1)证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9de7ea432599108b34a0ccaa0f2c75e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3ad459759b3a4ffa2550cddc9c6b0e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
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【推荐1】在四棱锥
中,平面
平面
,底面
为直角梯形,
,
,
,
为线段
的中点,过
的平面与线段
,
分别交于点
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/18446648-15ac-4274-89b0-6af0f2ce832a.png?resizew=172)
(1)求证:
;
(2)若
,是否存在点
,使得直线
与平面
所成角的正弦值为
,若存在,请确定
点的位置;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5acb763021bf166ca719d07223591d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4795ee1f96b430529934e2231b38885d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/639bec6242a4b3f7bfb4b7033a67328c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/18446648-15ac-4274-89b0-6af0f2ce832a.png?resizew=172)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1669c75e80a86a3ab27b660322fed353.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8254b52b379a420c17d38334940b073.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5868de99a3e94b13316b0122f22d3f91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b2a698891d42c70b597f0da4f215f09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
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【推荐2】如图,在四棱锥
中,
底面
,
,
,
,
为棱
上一点.
![](https://img.xkw.com/dksih/QBM/2021/12/14/2872451579682816/2878792506867712/STEM/4da2c9e8b8824a7897fd0f7cb5bce543.png?resizew=285)
(1)求证:
;
(2)若
平面
,求
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13ff5ff92f2505a933d0213039f4c014.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68d31600cba2d5256c7e78b6122d6755.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b364e1ade1c80f93cab19387aad6a59c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdb2dd10731b99c0f4f89ee957f8a239.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/2021/12/14/2872451579682816/2878792506867712/STEM/4da2c9e8b8824a7897fd0f7cb5bce543.png?resizew=285)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7dac702fe64edf1bc265da4b98cf2a0.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31c34b18525831f3eda7bb90be0199b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccaee8f228ff24e7c89879bb5b999cf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
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解题方法
【推荐1】已知四棱锥
中,底面ABCD为平行四边形,
底面ABCD,若
,
,E,F分别为
,
的重心.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/19/a7720b20-45ce-4f05-95dd-48d4c3c842cc.png?resizew=205)
(1)求证:
平面PBC;
(2)当
时,求平面PEF与平面PAD所成角的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d6baf49925a5bcb359b542d45067c81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83a04565a8ebaa111894b724b0ba266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2205cffebf8c4d5f81d15ed7b85c8936.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/177678001b2ccde1db8f57fa5e017002.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/19/a7720b20-45ce-4f05-95dd-48d4c3c842cc.png?resizew=205)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2951b9f77413d5f062acb300b09de1f6.png)
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【推荐2】等边三角形
的边长为4,CD是AB边上的高,E、F分别是AC和BC边的中点,现将
沿CD翻折成直二面角A-DC-B.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/95ed1e90-0797-460a-b3d5-aa650ff0c86c.png?resizew=324)
(1)试判断直线AB与平面DEF的位置关系,并说明理由;
(2)求平面
和平面
夹角的余弦值;
(3)在线段BC上是否存在一点P,使
?若存在,请指出P点的位置,若存在,请说明理由
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/95ed1e90-0797-460a-b3d5-aa650ff0c86c.png?resizew=324)
(1)试判断直线AB与平面DEF的位置关系,并说明理由;
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134ef0b1a2669a09f05bd4dc2496f706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14eec658f69c267a70c1e8f9b744e282.png)
(3)在线段BC上是否存在一点P,使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e32cf73c01995c91c3523fa11b3bd7d.png)
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【推荐3】如图,四边形
是正方形,
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d616ba305000c5de0a916c1166391bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
为
的中点,
为
的外心.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/21/01d5d36b-bf18-44d4-8435-df7226fa2346.png?resizew=127)
(1)求证:
平面
;
(2)求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d616ba305000c5de0a916c1166391bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4cf0fcbc301a936a916f6ff68037790.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f2281cb6df0c3c518ce5ed19a02b57e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/21/01d5d36b-bf18-44d4-8435-df7226fa2346.png?resizew=127)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ce03b310edce42191f9fa75a1c909ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/149596fee6ed1e2d19fd8dadc14a8baf.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/149596fee6ed1e2d19fd8dadc14a8baf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a09d9d486b7f91ba933210dd013a7f2c.png)
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