已知如图,四边形
是直角梯形,
,
,
平面
,
,点
、
、
分别是
、
、
的中点.
![](https://img.xkw.com/dksih/QBM/2015/8/12/1572211387195392/1572211393249280/STEM/a732b226c8b24dbb86c8667f3f0318bd.png)
(Ⅰ)求证:
平面
;
(Ⅱ)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34b0c4c783dd55685bd3e88bb31c6696.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e86664b23318cad2b9efe275db14319.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69e4fc0a2909fb2024ada132ed556dac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1805f86ef03c1084189b49f38a80334.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34b0c4c783dd55685bd3e88bb31c6696.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e106731c1b6c6622147b05aec6343ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33ebbd866e455cf80ea669c9f56f792c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2391c0e2fc44598610d519dacb778062.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4c783bab7586f60dc14d4f10b6d5b12.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9344dfa876a21ad6909eb449cda7dfd4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/435f34602291e9e293ff64a1606e29dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db9eb6113babcbbaa354055abde1d5f6.png)
![](https://img.xkw.com/dksih/QBM/2015/8/12/1572211387195392/1572211393249280/STEM/a732b226c8b24dbb86c8667f3f0318bd.png)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38b32ffe3903376b91697759f0fec552.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2802c01d5fa86f1ea79a2dfd2b7aac98.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/018f1af31cdc3be174abdbdff32308c5.png)
更新时间:2016-12-03 16:55:10
|
相似题推荐
解答题-证明题
|
较易
(0.85)
【推荐1】如图, 在直三棱柱
中,
,
,点
是
的中点,
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/450e98a3ea5e4b589092d2db6c72d0a4.png)
(1)求证:
;
(2)求证:
;
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/bb731e42b81d41c8ab0c8b55572d2003.png)
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/a6c598663bd3427fb1b5a131a1535b14.png)
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/7cde3b9b66d040faab3fccece6f0a397.png)
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/bf521fc3ced9486f96f5ee74aa1ef96b.png)
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/935f3c20fadb40d9b84cba8631cb83be.png)
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/450e98a3ea5e4b589092d2db6c72d0a4.png)
(1)求证:
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/d84010abb35d45f795329b635819e0e9.png)
(2)求证:
![](https://img.xkw.com/dksih/QBM/2017/2/14/1625075043794944/1625075044212736/STEM/58ee60c849014249a319450771c86a32.png)
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解答题-证明题
|
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【推荐2】如图,在四棱柱
中,已知平面
,
且
.
![](https://img.xkw.com/dksih/QBM/2015/1/5/1571947852431360/1571947857870848/STEM/1a73a8d953244d54ad924801ad15ee0f.png)
(1)求证:
;
(2)在棱BC上取一点E,使得
∥平面
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8456cee87c4e22351affc28f3a73a0f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d613aaea78414a0f875f39a5e0b65857.png)
且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe58eba1cb939e7d614827f86ef0ff94.png)
![](https://img.xkw.com/dksih/QBM/2015/1/5/1571947852431360/1571947857870848/STEM/1a73a8d953244d54ad924801ad15ee0f.png)
(1)求证:
![](https://img.xkw.com/dksih/QBM/2015/1/5/1571947852431360/1571947857870848/STEM/401f5ab2058b433d8b26c517d0166203.png)
(2)在棱BC上取一点E,使得
![](https://img.xkw.com/dksih/QBM/2015/1/5/1571947852431360/1571947857870848/STEM/f644b455c1914d979e5697d4be5e6116.png)
![](https://img.xkw.com/dksih/QBM/2015/1/5/1571947852431360/1571947857870848/STEM/afee3d5dd8b14785af96a238a9c2561b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8915a3686bd9b0e04223907bf56e89ba.png)
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解答题-证明题
|
较易
(0.85)
【推荐1】如图,△ABC是直角三角形,∠ABC=90°,AP⊥平面ABC,且AP=AB,点D是PB的中点,点E是PC上的一点,
![](https://img.xkw.com/dksih/QBM/2016/3/8/1572526138220544/1572526144274432/STEM/e5a10a92a7c64ac8a62d8d55ff5c1f34.png)
(1)当DE∥BC时,求证:直线PB⊥平面ADE;
(2)当DE⊥PC时,求证:直线PC⊥平面ADE;
(3)当AB=BC时,求二面角A﹣PC﹣B的大小.
![](https://img.xkw.com/dksih/QBM/2016/3/8/1572526138220544/1572526144274432/STEM/e5a10a92a7c64ac8a62d8d55ff5c1f34.png)
(1)当DE∥BC时,求证:直线PB⊥平面ADE;
(2)当DE⊥PC时,求证:直线PC⊥平面ADE;
(3)当AB=BC时,求二面角A﹣PC﹣B的大小.
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解答题-证明题
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(0.85)
【推荐2】如图,在三棱锥
中,
.
![](https://img.xkw.com/dksih/QBM/2016/9/7/1573004456312832/1573004461760512/STEM/2b0b0bdc062d446bad6333c2c85303ab.png)
(Ⅰ)求证:
;
(Ⅱ)求三棱锥
的体积.
![](https://img.xkw.com/dksih/QBM/2016/9/7/1573004456312832/1573004461760512/STEM/404dc33059ad4b789729530b4c8ffb17.png)
![](https://img.xkw.com/dksih/QBM/2016/9/7/1573004456312832/1573004461760512/STEM/fe7ce458ad1c406bb9d472ebc18b6f58.png)
![](https://img.xkw.com/dksih/QBM/2016/9/7/1573004456312832/1573004461760512/STEM/2b0b0bdc062d446bad6333c2c85303ab.png)
(Ⅰ)求证:
![](https://img.xkw.com/dksih/QBM/2016/9/7/1573004456312832/1573004461760512/STEM/a01308ab32774397937e2ea60445d476.png)
(Ⅱ)求三棱锥
![](https://img.xkw.com/dksih/QBM/2016/9/7/1573004456312832/1573004461760512/STEM/404dc33059ad4b789729530b4c8ffb17.png)
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(0.85)
解题方法
【推荐3】如图,在四棱锥
中,
为
的中点.
(1)若
,
,求证:
平面
;
(2)若
,平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
平面
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34e0a957a55460c72673c0f2ee90dbb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e839ac941e8bf536ff35a12e56c7a400.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f369bec2d5682bf6b8b317a08aff546.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62974d34de3a12418d6b700420afd1b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03203dd5ac79dd8c6707e4340773359.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdfa54114f04a75b8c96165b3718ed7f.png)
![](https://img.xkw.com/dksih/QBM/2017/6/29/1719197939507200/1719584469590016/STEM/84afe2736ca74c659fd549a260b09ba9.png?resizew=184)
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