如图,
为矩形,
为梯形,平面
平面
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/16/e203ce5f-037d-48c8-bb07-1f35f66669d4.png?resizew=202)
(1)若M为
中点,求证:
平面
;
(2)设平面
平面
,试判断
与平面
能否垂直?并证明你的结论;
(3)在(1)条件下,求平面
与平面
所夹的锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5bf51c07144386bd23a422d9ceb140.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6379891c7150af4188b5ab746d703bae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d20fec32122b4a70b993976201c9ba9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0046177466c78f08d45449dc5639bf38.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbe7a201432af0a2f9d21c6803906f5c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/16/e203ce5f-037d-48c8-bb07-1f35f66669d4.png?resizew=202)
(1)若M为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8197bf06d017950c85c3ba6a291c095e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df21b7b7a47318ef2bb069450c39f1cd.png)
(2)设平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c659d2ab07b9b66ed9a60cb604dd9aa7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b951997af111a840cb333a082137402.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(3)在(1)条件下,求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df21b7b7a47318ef2bb069450c39f1cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
更新时间:2023-11-12 01:29:09
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】如图,在四棱锥
中,
平面
,
,底面
是梯形,
,
,
,
为棱
上一点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/8f5f9d96-8e3d-4316-a437-3bf24e6772d0.png?resizew=178)
(1)若点
为
的中点,证明:
平面
.
(2)
,试确定
的值使得二面角
的大小为
.
![](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/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37002ada5d194d4d062fa3285d7d9824.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68d31600cba2d5256c7e78b6122d6755.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16114c73382b18f060150f2ab1f1484d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64f1161e0345b3646c71365430dccbb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/8f5f9d96-8e3d-4316-a437-3bf24e6772d0.png?resizew=178)
(1)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8f3abe8876333c19ae7e36c98a9329b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15b0f3113c3f27977a094b87b24fe042.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32bff9fff7a158e95a7f5041629e7a55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d5bca00fa20e6e80480b9d06d2e52ee.png)
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解题方法
【推荐2】如图,在长方体
中,
,
,点
是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/13/b5dd2a05-a064-4c45-a2cb-93b7ed2e9ddf.png?resizew=159)
(1)求证:
平面
;
(2)求异面直线
和
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efc6e4b936d7a800e839a30c3839574d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4622aff92fac94916af14f0e913e021.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/13/b5dd2a05-a064-4c45-a2cb-93b7ed2e9ddf.png?resizew=159)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcc3f049152c43dd29b12d0a60aa79f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6c607775591ff90104cc9c6ce07f919.png)
(2)求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83c09eec4e14a861af83d7828797d176.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2eb89294b31ffdd2680b4361e8994d7.png)
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【推荐1】如图,在三棱台
中,平面
平面
.
平面
;
(2)若直线
与
距离为3,求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85a2e10a5aebe40a9018d5ee3ade7af8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a107c59fd7206016c715086000cf57e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56fdf217165748fafe938b64fa08179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
(2)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
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【推荐2】如图,在四棱锥
中,底面
为直角梯形,
,
,
,
,Q为
的中点.
![](https://img.xkw.com/dksih/QBM/2022/1/11/2891973486723072/2892019527532544/STEM/4b2f6d44d758480097ab01a00d026618.png?resizew=142)
(1)求证:
;
(2)若平面
底面
,点E在棱
上,
,且二面角
的大小为
,求四棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dceb5cc71fc50f20649f6b9535fd914.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/815ecd052a57624aaa779744ba1e3e59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d7fca40920c70c01c551e83d61e69b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/2022/1/11/2891973486723072/2892019527532544/STEM/4b2f6d44d758480097ab01a00d026618.png?resizew=142)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf6c62979a7aa534a191d8387a741e8.png)
(2)若平面
![](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/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b384315ba84cafb978ef3619c8162b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6acec10372510a0edfc63e78af5dfaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a97bb4dcfab4ec7539bc783d563c49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
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【推荐3】已知四边形
是菱形,四边形
是矩形,平面
平面
,
,
,G是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/28/eff0fa38-5a0e-449e-bb84-ddc71b80cdf2.png?resizew=160)
(1)证明:
平面
;
(2)求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd4b93d7abcfc4c3df48f03aa969c17f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2a4e3f0349fa83dc2a0b7d798f04843.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/077e97453ae00a89df35be3a0b722df2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/28/eff0fa38-5a0e-449e-bb84-ddc71b80cdf2.png?resizew=160)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f220434c51562f59e302899804899954.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ae8768996ca9a0f2c5d9a19abbd54df.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7267f2934c256fd74e58cb62d685bba0.png)
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【推荐1】如图,在四棱锥
中,底面
是直角梯形,
,
,
是等边三角形,侧面
底面
,
,
,
,点
、点
分别在棱
、棱
上,
,
,点
是线段
上的任意一点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/5/516961b3-d1e9-41be-b308-b25d53cb424f.png?resizew=247)
(1)求证:
平面
;
(2)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.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/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25df618ec33cee978f79d2eae62024f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/448cbac9a1ef3de7538a6b30cdc39582.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/077c956ac0eb05cf120e14f17413dfa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f8eeeea1c9652cacce976f8129cf520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f4aca5534bce25acaeb7379deed8f8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d4db9b82b67efe45a02fca32bfcf5dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1bd1adfe4cc6566218f19970c2fd3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d806ee794a202bb50faf7a452664108.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73d65319fd396b9fd220f7a95a7a6042.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/5/516961b3-d1e9-41be-b308-b25d53cb424f.png?resizew=247)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/011abe509df00fe9410ab08b585ad7db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef796b46e68fe77b117ff0483d2370c.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ceaf82ddc867b772e8a0e473f9b8a18b.png)
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【推荐2】四棱柱
中,
底面
,
为
的中点.
(1)求证:
;
(2)求面
与面
夹角的余弦值
(3)设点
在线段
上,且直线
与平面
所成角的正弦值为
,求线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c853a0857121371ea70eda43138b2a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce6050904e054d1b59896777d08d1073.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/10/da011a76-fc18-4beb-914e-541e24b6f4d7.png?resizew=151)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/965f2b693156aa69dcd9568e4545d0dc.png)
(2)求面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/458b6c0e45659c2e506386ebd8ea0647.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ae0175429545dceaf6b7038e421e764.png)
(3)设点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e516121599c9fcc528121c00afcf52fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0467b0675c3ecfb282cc88255284d3e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
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适中
(0.65)
【推荐3】如图所示,在三棱锥
中,D,E,F分别是棱
的中点,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f281f844598cad6089f9df44cf3487e4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/69257ac2-69c0-454c-b662-35499fc7ee78.png?resizew=130)
(1)证明:
;
(2)若
,
,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e335309cb5c40e4b3c5d9ceedbf9f887.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cbb05b8b630052ff544249ebd72d95d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f281f844598cad6089f9df44cf3487e4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/69257ac2-69c0-454c-b662-35499fc7ee78.png?resizew=130)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a15a004f7d47ed595f063e60075223a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb5b12692517a39c320f99a479eb055.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080ca48cd27d4bf9d9ef084b558fc17a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13259de331de43dda25f2688b7822663.png)
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名校
【推荐1】刍(chú)甍(méng)是几何体中的一种特殊的五面体.中国古代数学名著《九章算术》中记载:“刍甍者,下有袤有广,而上有袤无广.刍,草也.甍,屋盖也.求积术曰:倍下表,上袤从之,以广乘之,又以高乘之,六而一.”翻译为“底面有长有宽为矩形,顶部只有长没有宽为一条棱.刍甍字面意思为茅草屋顶
”现有一个刍甍如图所示,四边形
为长方形,
平面
,
和
是全等的等边三角形.
;
(2)若已知
,
①求二面角
的余弦值;
②求该五面体
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06222ee533c2484ab25321a6abbf98cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6830ebecddbd9759be626289c408e4f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70099a8a0e7cff25485a63e8811a6aab.png)
(2)若已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c589c8207e40ad3355bbb8167de3486.png)
①求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a34e44c5d7e1d22521fb293994f5b0.png)
②求该五面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
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解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图,在三棱柱
中,
平面
是线段
上的一个动点,
分别是线段
的中点,记平面
与平面
的交线为
.![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
;
(2)当二面角
的大小为
时,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad9d769cab78858e4489b821e3953df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cca04b2a2b61d62a809776670a60c09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134ef0b1a2669a09f05bd4dc2496f706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99b16cff607cdc2d69afc70dc778acbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
(2)当二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0f1592b2ad60fa438c2564ff651231f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/231b861d6d1f1d0b9f52b041cb40eb62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐3】在四棱锥
中,底面
为正方形,
与
相交于
点,
为
的中点.
平面
,求证:
平面
;
(2)求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5c262adacfc278d397a0ca74d354416.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1084a42a7b7600ac9651a023de6d3401.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebae74545340ce6971f437d129e9c659.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9df740160690029ac1e730c85f20347.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9ccffcde07fcc0f694779707c126860.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/745e0525a41fe2e2a7739c75a942290b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2b347a48a3e9785e2733528de68cc4b.png)
您最近一年使用:0次