如图,在三棱柱
中,
平面
,
,
,点
为
的中点.
![](https://img.xkw.com/dksih/QBM/2017/10/3/1787390365204480/1787416693751808/STEM/c4431ca986584309adc646febb206bf3.png?resizew=205)
(1)证明:
平面
;
(2)求三棱锥
的体积.
![](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/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/615fc8790237a1b09af51d6bcad6b595.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e96a6b20a35af7755e5d90789ea862da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/2017/10/3/1787390365204480/1787416693751808/STEM/c4431ca986584309adc646febb206bf3.png?resizew=205)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5274f8f92e3707b9dc5ac2e915c94d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f62fd0b510920be6bc60d170c3ff3da3.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2bc3a84440adf082b738e385ed7020a.png)
更新时间:2017-10-03 18:11:29
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】在四棱锥
中,底面
是直角梯形,
,
,
,
.
![](https://img.xkw.com/dksih/QBM/2019/1/31/2130792194359296/2130820243431424/STEM/6a0db4b3-8d1d-4b6f-9cc9-28e7e935a1dd.png)
(1)求证:平面
平面
;
(2)若三棱锥
的体积为
,求
的长.
![](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/b37591109b0a0ec5ffe2133f83310eca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8af620f6d204d310d8e3f267fdd6c3f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d4a10bd8ebd69bf1b06436ae3841394.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c383691e8d740830a865b12d66f7633.png)
![](https://img.xkw.com/dksih/QBM/2019/1/31/2130792194359296/2130820243431424/STEM/6a0db4b3-8d1d-4b6f-9cc9-28e7e935a1dd.png)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
(2)若三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b183492677d0457b8701c53d9fa1414.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24c14ff9b66f21c05e52dc3c8908c2df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
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适中
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解题方法
【推荐2】如图,三棱柱
中,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/28/236bf01c-4b29-4afb-84b7-8ff4d14f2ffc.png?resizew=186)
(1)证明:
;
(2)若
,
,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe2010a4b6fb8908822754aca5231c32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/241c46ad40761310d3a1ef6d2bafe37f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad92b50301d4a69a68be7668dfd62347.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c06c764a9e2d855ce09d8bff3c6048ed.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/28/236bf01c-4b29-4afb-84b7-8ff4d14f2ffc.png?resizew=186)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34eef031ddc61e92a09067d80e4e075f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/239379a84c5918e091e6e72c2e12d990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d986cb6bfc4eb59121d0fca4fd71dbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ab9fc4bdb40e0f468f32e74fb399980.png)
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解答题-问答题
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适中
(0.65)
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解题方法
【推荐1】如图,等腰梯形ABCD中,AD=DC=BC=2,AB=4,E为AB的中点,将△ADE沿DE折起、得到四棱锥P-DEBC,F为PC的中点,M为EB的中点
平面PDE;
(2)证明:DE⊥PC;
(3)当四棱锥P-DEBC的体积最大时,求三棱锥E-DCF的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb31ef428bd9de9bc875b343feded3c7.png)
(2)证明:DE⊥PC;
(3)当四棱锥P-DEBC的体积最大时,求三棱锥E-DCF的体积.
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【推荐2】如图1,在直角梯形
中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
,
,点
为
的中点,点
在![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94214b5db2aaa2f0ec33fb3364237b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
,将四边形
沿
边折起,如图2.
![](https://img.xkw.com/dksih/QBM/2022/4/4/2951134094770176/2954224430669824/STEM/ff8fb79c-00a1-4412-bd2e-c030bd31e7e4.png?resizew=279)
(1)证明:图2中的![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
平面
;
(2)在图2中,若
,求该几何体的体积.
![](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/2a9bfa68259d7a331be323b2038d628a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94214b5db2aaa2f0ec33fb3364237b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f08ff2c55514a933ae4c57e091d1a5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea2f3df5713a423887c16e6355236372.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/2022/4/4/2951134094770176/2954224430669824/STEM/ff8fb79c-00a1-4412-bd2e-c030bd31e7e4.png?resizew=279)
(1)证明:图2中的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
(2)在图2中,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d4746df85049d1651d3f6c30212a7a9.png)
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解答题-问答题
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适中
(0.65)
【推荐3】在如图所示的几何体中,平面
平面
,四边形
为等腰梯形,四边形
为菱形.已知
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/62437b53-c258-4755-8bbd-89fe9fd6a1f4.png?resizew=197)
(1)线段
上是否存在一点
,使得
平面
?证明你的结论.
(2)若线段
在平面
上的投影长度为
,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/393a753b57da192086a617f26ec89aea.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/18d5a164bf56f8fb92527ad78bc10ccf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa1dbe93ef097e1aa25b19128728b441.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/62437b53-c258-4755-8bbd-89fe9fd6a1f4.png?resizew=197)
(1)线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6ae72f5e5891249caa10c43224da89c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdef69f2de407ccaa28c7241d52e2d44.png)
(2)若线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fa3254460ecbacecb3e57c5dce227f4.png)
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