如图,在直三棱柱
中,
,
,
为
中点,
与
交于点
.
(1)求证:
∥平面
.
(2)求证:
平面
.
(3)在线段
上是否存在点
,使得
?请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fd8f940b796af67206b3f9dd410a407.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.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/1dde8112e8eb968fd042418dd632759e.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5888bec948373f3854258ad80171073d.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e16f65c3a318220c2f5baac171bbb61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a211ad5a06b505b8365a62c1946f3cb7.png)
(3)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff24d05b5b9502c2be337f9be84fe4ed.png)
![](https://img.xkw.com/dksih/QBM/2017/11/3/1809219827998720/1809781657174016/STEM/f692824c8777477c8bc92199c93a385e.png?resizew=181)
更新时间:2017-11-04 08:33:07
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,在正三棱柱
中,
是侧面
对角线的交点,
是侧面
对角线的交点,
是棱
的中点.求证:
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/10/d682ad80-c22e-4392-9635-0d07fce31309.png?resizew=148)
(1)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
平面
;
(2)平面
平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ac61c24f99a4e466f1e2ea011893866.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/10/d682ad80-c22e-4392-9635-0d07fce31309.png?resizew=148)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6501f1c913a4ef64957a2f01ab5baa15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfb3f0b5d8bf98eeff66f43b7dcbb4be.png)
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【推荐2】如图1,在边长为
的正方形
中,点
,
分别是
,
的中点,点
在
上,且
.将
,
分别沿
,
折叠,使
,
点重合于点
,如图2所示.
![](https://img.xkw.com/dksih/QBM/2020/1/9/2373268910227456/2374244518969344/STEM/d9982f462e5a40dbaf487c2c22dbec77.png?resizew=219)
图1 图2
(1)求证:
平面
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e26b615f11fd107ef65c07f5c3f18da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ccbf98ff1b1f121ee3aa3dec108ba0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b6fdadad5411ba41fae9277326f49cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://img.xkw.com/dksih/QBM/2020/1/9/2373268910227456/2374244518969344/STEM/620873d03ed44fac86387236cbac2c4a.png?resizew=168)
![](https://img.xkw.com/dksih/QBM/2020/1/9/2373268910227456/2374244518969344/STEM/d9982f462e5a40dbaf487c2c22dbec77.png?resizew=219)
图1 图2
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30067b7b236d17af8a462f96a58d11bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed4cba9d2412e4a28f8740bddd5738d4.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/082f61a171c1bd681e153bfdb8b34b24.png)
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适中
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名校
【推荐1】如图,四面体
中,
,
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/2020/1/2/2368530279997440/2369360141246464/STEM/a45ef089419b41248d5f29738b12bc94.png?resizew=220)
(1)证明:
;
(2)已知
是边长为2正三角形.
(Ⅰ)若
为棱
的中点,求
的大小;
(Ⅱ)若
为线段
上的点,且
,求四面体
的体积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24914bb2ddc7a5d0cb8772ea5fd31401.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91ee4a6a3380d56e876c8bb7f04ef53d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/701f3b0e2bedfe5195443459072d798e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/2020/1/2/2368530279997440/2369360141246464/STEM/a45ef089419b41248d5f29738b12bc94.png?resizew=220)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a97ec8912352afb1a702924163d75daf.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9bcdc38238794c82e7cd92fa4ab7af99.png)
(Ⅰ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60dc9f8e47e78b7f4ab2dd9cd559f601.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fe7222603916a937e6a59313cff475e.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60dc9f8e47e78b7f4ab2dd9cd559f601.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/207d35fbb2504a3e9f4aafdb80b7a96a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55bf39b6c78f5b45d8e5e908960e2cf5.png)
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解答题-证明题
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【推荐2】如图,在五棱锥
中,
平面ABCDE,
,
,
,
,
,
,
是等腰三角形.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/09fe5e4d-e59b-4809-930d-087e4d49bcae.png?resizew=189)
(1)求证:
平面PAC;
(2)求由平面PAC与平面PED构成的锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be89b9d1709d7974a108142c5fa2ccec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b37591109b0a0ec5ffe2133f83310eca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e29fe63de5a8ec982803f827260a190c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bc1471daca52937ea30b7a2f00cdb22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0434c0177ca5c88ec129bd4cc13f4a1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080ca48cd27d4bf9d9ef084b558fc17a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f42fcb730e00ae46399217ad27718d49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53502463cc76201000e02df314e58769.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/09fe5e4d-e59b-4809-930d-087e4d49bcae.png?resizew=189)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97f30533da2e1d2a958dc906c37eba9d.png)
(2)求由平面PAC与平面PED构成的锐二面角的余弦值.
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名校
【推荐1】如图,在直三棱柱
中, AB=1,
,∠ABC=
.
(1 )证明:
;
(2)求二面角A—
—B的正切值.
![](https://img.xkw.com/dksih/QBM/2012/6/16/1570888444502016/1570888450097152/STEM/48cf4a2fa71c445989fbaebec855e8ef.png?resizew=96)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/126a3d8d69d4623cefbd444020e92db5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d5bca00fa20e6e80480b9d06d2e52ee.png)
(1 )证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba985fb50a9078a839b66bf1d1eadea9.png)
(2)求二面角A—
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://img.xkw.com/dksih/QBM/2012/6/16/1570888444502016/1570888450097152/STEM/3d414a2757f3451b826262fbd9c92e5d.png?resizew=220)
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解答题-问答题
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适中
(0.65)
解题方法
【推荐2】如图,在三棱锥
中,
,
,
两两垂直,
,平面
平面
,且
与棱
,
,
分别交于
,
,
三点.
![](https://img.xkw.com/dksih/QBM/2018/5/23/1951678313824256/1952933369798656/STEM/87ddd21a520e45019a0dea3377f01162.png?resizew=156)
(1)过A作直线
,使得
,
,请写出作法并加以证明;
(2)若
将三棱锥
分成体积之比为
的两部分(其中
的体积更小),
为线段
的中点,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e43f6eb62e48e72e06361138e0d1e4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78f4235bce509940f8f7fb0ca9ee1345.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32141fcc158ce9d87532092dfe3725f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07c9121cede0ee0562e23b8a26b34616.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4f1b40221f57567c67c1ba5ceb2f57b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9721059d158853671eaf19e39769b13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0758f3ff9f1f7109024c1ef65536c58.png)
![](https://img.xkw.com/dksih/QBM/2018/5/23/1951678313824256/1952933369798656/STEM/87ddd21a520e45019a0dea3377f01162.png?resizew=156)
(1)过A作直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a159de0b2d9eb1ae0b7e664e64d3c6c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7609c21147d4fc37e9268974cde61da4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db6325ab9ab5b6334809df7af8a4cef0.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07c9121cede0ee0562e23b8a26b34616.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e43f6eb62e48e72e06361138e0d1e4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e71c4c6368acaabb14efc2cfd0ed365.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b575c223f5ff124f95346949d7b2a55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/289d7a880379d6060065c829b45b0ed6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/488c9cb4d88938d832617f520a3ca951.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8635d5596a3dba186d2e551dd0ccd7b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90fa72b4a24aeab96fa747e8abda00d3.png)
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