如图,在正三棱柱
中,
为线段
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/db489e20-2563-4df9-8c9e-32875f628baf.png?resizew=220)
(1)求证:直线
平面
;
(2)设
为线段
上任意一点,在
内的平面区域(包括边界)是否存在点
,使
,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/db489e20-2563-4df9-8c9e-32875f628baf.png?resizew=220)
(1)求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1496afecd92a619fbe5e9b736f06f4e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a935b7d21a103a264b6e96ecf82dbe4a.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60476ff27b009fae801d39d0d31a2f8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd5260b9927d0ad83b03c1e24c586e98.png)
更新时间:2019-12-23 22:10:39
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,在平行六面体
中底面
是边长为
的菱形,
,
为
的中点,
为
上一点,
平面
,
.
![](https://img.xkw.com/dksih/QBM/2021/6/5/2736615037394944/2803263199297536/STEM/7d0879f4-1678-4340-903c-795feba051d5.png?resizew=257)
(I)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c02ffbf0d9a3a73b896732082710c2f.png)
(II)若
,
,①求证:该平行六面体为直四棱柱;②求二面角
.
![](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/95bacae35b6e16a0a33c2bdc6bc07df7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10d8eb4a9f462ca0c1d49c3fe91e720d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f306ff6d237cd9d847aa109acf9333d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70db40c42655327adee01caedfc9d50c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efc55d282b5786fc0ac1fcf7e706e3a1.png)
![](https://img.xkw.com/dksih/QBM/2021/6/5/2736615037394944/2803263199297536/STEM/7d0879f4-1678-4340-903c-795feba051d5.png?resizew=257)
(I)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c02ffbf0d9a3a73b896732082710c2f.png)
(II)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e55a2310cbba5e050488cd9296eb195d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e5c289b8aabdbfba95c7fd1e1842f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05d2c1b3fd7524383736c72f4c0f1f27.png)
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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,在三棱柱
中,
为正三角形,
,
,
,点
在线段
的中点,点
为线段
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/10/7a2fdff2-cf24-4f93-92d7-e33a3af0ace3.png?resizew=233)
(1)在线段
上是否存在点
,使得
平面
?若存在,指出点
的位置;若不存在,请说明理由.
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a72935e227f601eae1c9558d7aeddbb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98474425eb86a28f2b01cec95643ae7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/615fc8790237a1b09af51d6bcad6b595.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/209acf15985d1ea1ad86fc4a37e38c0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00de3b5f3920068743971c8f05638863.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/10/7a2fdff2-cf24-4f93-92d7-e33a3af0ace3.png?resizew=233)
(1)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/903dc68a0352d0201f2ed22267a12b1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1253885737cd104e24ddd2d4c96e4c86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2e3bcd0df1bc8fda7ac4df343c7924d.png)
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解题方法
【推荐3】如图所示,在直三棱柱
中,
,D为
的中点.
![](https://img.xkw.com/dksih/QBM/2021/4/27/2708887970865152/2774159417237504/STEM/9d1354cc1317498f924dc953521572e5.png?resizew=188)
(1)求证:
平面
;
(2)若
平面
,求证:
平面
;
(3)在(2)的条件下,设
,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea6ff6a807f5639faac835012b3728c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/2021/4/27/2708887970865152/2774159417237504/STEM/9d1354cc1317498f924dc953521572e5.png?resizew=188)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/547a4b438e2e6687c7cd55ea08bbaae2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d1d2e0f281222a5f289ea4008370aed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a59d296654aa17749f8300ae1d1da0e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
(3)在(2)的条件下,设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8511a1b768df56495af12fc303f869dd.png)
您最近一年使用:0次
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【推荐1】如图,直三棱柱ABC−A1B1C1中(侧棱与底面垂直的棱柱),AC=BC=1,∠ACB=90°,AA1=
,D 是A1B1的中点.
![](https://img.xkw.com/dksih/QBM/2018/10/12/2051988082130944/2054198921592832/STEM/5d21119a6d994c6c9296d704dfadd8fd.png?resizew=140)
(1)求证:C1D⊥平面AA1B1B;
(2)当点F 在BB1上的什么位置时,AB1⊥平面C1DF ?并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://img.xkw.com/dksih/QBM/2018/10/12/2051988082130944/2054198921592832/STEM/5d21119a6d994c6c9296d704dfadd8fd.png?resizew=140)
(1)求证:C1D⊥平面AA1B1B;
(2)当点F 在BB1上的什么位置时,AB1⊥平面C1DF ?并证明你的结论.
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解题方法
【推荐2】如图,在长方体
中,
分别为
的中点,
是
上一个动点,且
.
![](https://img.xkw.com/dksih/QBM/2018/6/15/1967883688271872/1968989227687936/STEM/28a4413f-9a06-47df-b56d-a77993c0ec15.png)
(1)当
时,求证:平面
平面
;
(2)是否存在
,使得
?若存在,请求出
的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f10249eeddc12b6bb18eb0123bdca62e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5125b4ddf851785aee54b5531e35a75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c64e86ddae6c991b61a149ea6057681.png)
![](https://img.xkw.com/dksih/QBM/2018/6/15/1967883688271872/1968989227687936/STEM/28a4413f-9a06-47df-b56d-a77993c0ec15.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/500d68f2678989a5ce7431cfd51b019d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cd89940c4729730f21d7719e16d7f1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/959b9393bde25615c5e9233bfd8e6a65.png)
(2)是否存在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31904028b0e9284d0887be294bbd8add.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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【推荐3】如图所示,已知四棱柱
,四边形
为直角梯形,
,
,
,平面
平面
,
.
![](https://img.xkw.com/dksih/QBM/2021/4/15/2700230680199168/2700531540860928/STEM/414e6afb-8aac-403e-91c1-311118841eee.png?resizew=276)
(1)若
为
的中点,
为线段
上的一动点,当
平面
,求
的长;
(2)在(1)的条件下,求二面角
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/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af260e0d98c95d1e092dc4c6d348e3ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c83914fcc01cb2d0bfbfa587233d7ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85a2e10a5aebe40a9018d5ee3ade7af8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/064a04589ae680482d23c3b08f820917.png)
![](https://img.xkw.com/dksih/QBM/2021/4/15/2700230680199168/2700531540860928/STEM/414e6afb-8aac-403e-91c1-311118841eee.png?resizew=276)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d862fc2fe541999e0c175d32e90a81ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c4e7552a39c412d882766dbcd7eeb69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
(2)在(1)的条件下,求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6ccd3bb218ecb3dc1319d24dca57f81.png)
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【推荐1】已知等腰梯形
,
.现将
沿着
折起,使得面
面
,点F为线段BC上一动点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/2/585ac82a-3cff-4d74-93f0-fdd20dac6219.png?resizew=338)
(1)证明:
;
(2)如果F为BC中点,证明:
面
;
(3)若二面角
的余弦值为
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6c116afaf8619f0a722883615429943.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1abcad002e8d35c72f3f96bd6244c17f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc3814287dbb60d478bffc5366f9928b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed5f0cfc1049f84a04c81bd213afb8d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6bfad3f7e65188bcf7f62ea5acdbf4a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/2/585ac82a-3cff-4d74-93f0-fdd20dac6219.png?resizew=338)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f64912cf9f1bccc365532ab1cb26481a.png)
(2)如果F为BC中点,证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40f44f2b2f82a9126223138972850aa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
(3)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0f1592b2ad60fa438c2564ff651231f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72acf5ee54c89dede4358c61ecd7a101.png)
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【推荐2】如图,在三棱台
中,已知平面
平面
,
,
,
.
(1)证明:
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/986ba572d8373df48c996f8c8611498c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d052663101ca930843abd98cbd61c19.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/de19416fa3c38b1b82abf0937573f9fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/283c8668ca30b171ee4352452e1c7e94.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/2/06047b09-1529-4036-8dc3-a21de78bf9d0.png?resizew=195)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5232ca3c1e0ce4064d0094502aacb063.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03edbab2be470153ed4ebe16c25430b9.png)
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