名校
1 . 如图,在正方形ABCD中,点E是AB的中点,点F是BC的中点,将△AED,△DCF分别沿DE,DF折起,使A,C两点重合于P,连接EF,PB.
(1)求证:
;
(2)点M是PD上一点,若
平面EFM,则
为何值?并说明理由;
(3)若
,求二面角
的余弦值.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/14/e1d57202-84cc-4ab8-b4fd-54dbcf6ed984.png?resizew=333)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d55bc62f8afd58b044a0c24bf361d0c5.png)
(2)点M是PD上一点,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30067b7b236d17af8a462f96a58d11bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced22fbe85d4a749c7b0b6bbae3ea3e7.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33458ba13d7c6278f6b9318e78ba917f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/948382a4c75dbb1dec52b444335989f1.png)
您最近一年使用:0次
2023-06-09更新
|
781次组卷
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4卷引用:海南省海口市华侨中学2018-2019学年高一下学期期末数学试题
2020高三·全国·专题练习
解题方法
2 . 如图所示,正方形
的边长为
,
、
分别为
、
的中点,
、
是平面
同一侧的两点,
平面
,
,
.
![](https://img.xkw.com/dksih/QBM/2020/12/6/2608413667966976/2609223078838272/STEM/3f054667dc6a452cab4a36367e2f59ac.png?resizew=358)
(1)设
,
为
上一点,若
平面
,求
;
(2)证明:平面
平面
.
![](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/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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39967d6f3aed6ce7b6643787795d451d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de2eae6af16797f2ab8efc6041806677.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3de3236e61ff954df9dd9872bf7d95e3.png)
![](https://img.xkw.com/dksih/QBM/2020/12/6/2608413667966976/2609223078838272/STEM/3f054667dc6a452cab4a36367e2f59ac.png?resizew=358)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a23f01af749100e1888bba06268843db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dafebaaf13781120dc57c277d0267c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ae7bf236e8637182a1553ce36bd9c67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94cc30d46b4538a4c86064df7460356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3892b3fc0601d3a4b567fac01d9b2a0.png)
(2)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae1f07df5692e4c4e2db643aefdd0d98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94cc30d46b4538a4c86064df7460356.png)
您最近一年使用:0次
名校
3 . 在正方体
中,E为棱CD上一点,且
,F为棱
的中点,且平面BEF与
交于点G,与
交于点H,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d80f818ec04fac85f28df16a1699846.png)
______ ,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3287d304d2892ad96edd6277d9e18bb6.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/795e740cb57615d48c36b416d5b93a9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24bb49fdc6b6bbb2449fdf8a0de769d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d80f818ec04fac85f28df16a1699846.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3287d304d2892ad96edd6277d9e18bb6.png)
您最近一年使用:0次
2020-02-01更新
|
742次组卷
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8卷引用:海南省2019-2020学年高三高考调研测试数学试题
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