名校
解题方法
1 . 如图,已知四棱锥
的底面
为菱形,且
底面
.
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458527760809984/2459046078365696/STEM/8389321b-8dc8-4594-a8be-93257f9c91c2.png)
(1)证明:平面
平面
.
(2)若
,且平面
与平面
所成锐二面角的余弦值为
,求
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458527760809984/2459046078365696/STEM/8389321b-8dc8-4594-a8be-93257f9c91c2.png)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f04c222223dae9ef27d4c132534d9848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/642a7dd471434c923f76809dfa5ee183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/715c21f2228f0ac61aa5b7a52329eaf3.png)
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2020-05-09更新
|
1920次组卷
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7卷引用:贵州省贵阳市四校2021届高三年级上学期第二次联合考试理科数学试题