名校
解题方法
1 . 如图,在直四棱柱
中,底面ABCD为菱形,且
,E为AB的中点,F为
与
的交点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/5dd4b6d5-628d-4e45-a359-b44b3e897073.png?resizew=194)
(1)求证:平面
平面
;
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/5dd4b6d5-628d-4e45-a359-b44b3e897073.png?resizew=194)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f6dd051db98c531f9ef18cdfd793f4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82b724168afaee2ecddf97257180be18.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/563f66dc8d106855477bd6f779bfd7a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ef52ef77e8f17927ce71c388dd3286a.png)
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2022-03-06更新
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3卷引用:重庆市四川外语学院重庆第二外国语学校2023届高三下学期开学考试数学试题