在四棱锥P-ABCD中,底面ABCD是直角梯形,AB
CD,∠ABC=90°,AB=PB=PC=BC=2CD=2,平面PBC⊥平面ABCD.
(1)求证:AB⊥平面PBC;
(2)求三棱锥C-ADP的体积;
(3)在棱PB上是否存在点M,使CM
平面PAD?若存在,求
的值.若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/4/4fc1c2ef-bc51-407d-97c8-7277426e28a6.png?resizew=165)
(1)求证:AB⊥平面PBC;
(2)求三棱锥C-ADP的体积;
(3)在棱PB上是否存在点M,使CM
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b505e0df1131e3a93fc81d13f6e224e7.png)
更新时间:2020-10-15 21:06:48
|
相似题推荐
解答题-证明题
|
适中
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【推荐1】如图,在平面几何中,有如下命题“正三角形
的高为
,O是
内任意一点, O到三边的距离分别为
,则
为定值;当O是
的中心时,O到各边的距离均为
”.
证明如下:设正三角形
边长为a,高h,O到三边的距离分别
,
则:
,即:
,
化简得,
,
(定值).
若O是
中心,则
,即:正三角形中心到各边的距离均为
.
类比此命题及证明方法,在立体几何中,请写出高为h的正四面体
(下图)相应的命题,并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eabd5f3a86afe49dcd70571e2b96cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc1bb38195f072eb306f7ff363d19d92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5c505ba75dad12754462008c14a22a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b265bcd9a636c4f85a5992438032db3.png)
证明如下:设正三角形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/367c96a0ff95b92877eda2a7c98871e1.png)
则:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d10989a6662118aa12f438854c6f1bc7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afca72943300013e376cabf814f241b7.png)
化简得,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64cb83e91782bf0f86cf6a8013ec480c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4ea2d12e7891885ab290c48c95c82cc.png)
若O是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcb93dd358c04249b78f9b4c023671c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b265bcd9a636c4f85a5992438032db3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/19/ac6cb224-269c-4187-b727-4c0ef10d6e92.png?resizew=176)
类比此命题及证明方法,在立体几何中,请写出高为h的正四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/19/eee51f67-73db-4254-8b07-3b54af2e6d5b.png?resizew=176)
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解题方法
【推荐2】已知三棱锥
中,平面
平面
,
.
(1)若
,求
与平面
所成角的正切值;
(2)当二面角
最小时,求三棱锥
体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78a3fd5284e160896f07ce367645fd04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15ba2b2354c1427e9f0f5cb8df4114b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a916d31a199e250556fb7478d9f57f7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/1/01fc211c-a4f0-49e4-b260-c90e7e686a16.png?resizew=191)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1be86349e06431647f8e359d9bd07700.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)当二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47d294d69caac577339f11f477b2047e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
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【推荐1】如图,在棱长均为
的三棱柱
中,点
在平面
内的射影
为
与
的交点,
、
分别为
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/4dcf618a-1664-4df2-88f8-f81efd99422b.png?resizew=249)
(1)求证:四边形
为正方形;
(2)求直线
与平面
所成角的正弦值;
(3)在线段
上是否存在一点
,使得直线
与平面
没有公共点?若存在求出
的值.(该问写出结论即可)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9b7b7793d29d66dfdd89e7a6564a35c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b470c4e195cf7a07b7a331ce4b436e03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f1f229274a6e17977cc047814212589.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/4dcf618a-1664-4df2-88f8-f81efd99422b.png?resizew=249)
(1)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9b7b7793d29d66dfdd89e7a6564a35c.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e53b212640dadf751ef7f65a78a209.png)
(3)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b470c4e195cf7a07b7a331ce4b436e03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74bca84ad86c648d3bb20c8909c8da3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e21468a972babcefc0028f2bd1f56336.png)
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【推荐2】在如图所示的四棱锥
中,四边形
是等腰梯形,
,
,
平面
,
.
;
(2)若
为
的中点,问线段
上是否存在点
,使得
平面
?若存在,求出
的长;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e5ba482836565abad208665cf7b9972.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05740f0c6071846227dc0ec177ad15e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7b5a90e556da12d63b7f481bd8e874c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a81de875a8c8fc6f7e70f31e4a2b80cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89b87b3be10408261827291574434d8e.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b8badfeb9e7556486e02ab60df4dd32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fa3254460ecbacecb3e57c5dce227f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
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解答题-问答题
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适中
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【推荐3】矩形
与矩形
的公共边为
,且平面
平面
,如图所示,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/6/76f8d678-9982-4367-beb8-5e74e5d0128a.png?resizew=212)
(1)证明:
平面
;
(2)求异面直线
与
所成角的余弦值;
(3)若
是棱
的中点,在线段
上是否存在一点
,使得
平面
?证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dde327febef2331a4766a79b433cc02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cf9a6db3571fa57bfa2d5e4d44c51b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dde327febef2331a4766a79b433cc02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ead5afc991f6af5a7a3597fb5552d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfad18b17876aa9485baf303be88710e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/6/76f8d678-9982-4367-beb8-5e74e5d0128a.png?resizew=212)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4c3f9dd5d0343597a7f58a1989b537.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2db1674add0f4a1a24f5ed893b1c5d0.png)
(2)求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
(3)若
![](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/00bab17635a999236e8d2e35017a208d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7592c4f01c8e06c7ee90df5b9413a9f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2db1674add0f4a1a24f5ed893b1c5d0.png)
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名校
【推荐1】如图,已知四棱锥
的底面是等腰梯形,
,
,
,
,
为等边三角形,且点P在底面
上的射影为
的中点G,点E在线段
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/ba2b02a1-8f3f-4348-99b9-30b5debab1bd.png?resizew=210)
(1)求证:
平面
.
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65a3e478bb87d094e3a0af30dd10ae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55a675310c8ba418e5a59beb7317e21e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddf9cfe8e82be4276543d0c0694b1152.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/23/ba2b02a1-8f3f-4348-99b9-30b5debab1bd.png?resizew=210)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d2d217e9bcd059908f117dfc4d4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a65bf87f74420270138ed73a2d38ca48.png)
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解题方法
【推荐2】如图,已知圆锥的顶点为,底面圆心为
,高为3,底面半径为2.
(1)求该圆锥侧面展开图的圆心角;
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55b9931cfb6a0ba33cb6e11e569a8cee.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/892909e49156f7dcc0650fcd65243877.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
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