名校
解题方法
1 . 在正方体
中,
为正方形ABCD的中心,则直线
与直线
所成角的余弦值为( )
![](https://img.xkw.com/dksih/QBM/2022/4/24/2965230716051456/2972048775421952/STEM/4a5765c6-f458-40ca-abb1-a399c3ea3729.png?resizew=180)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e539f26ed5e0b20ff7220559324869a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/172e5fbd9df8b19e0786fad909d36d63.png)
![](https://img.xkw.com/dksih/QBM/2022/4/24/2965230716051456/2972048775421952/STEM/4a5765c6-f458-40ca-abb1-a399c3ea3729.png?resizew=180)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
2022-05-04更新
|
851次组卷
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6卷引用:河南省名校2022届联盟全国高考冲刺压轴(一)理科数学试题
河南省名校2022届联盟全国高考冲刺压轴(一)理科数学试题河南省开封市天成学校2023届高三理科数学试题河南省开封市天成学校2023届高三文科数学试题安徽省阜阳市临泉第一中学2021-2022学年高二下学期第三次月考数学试题(已下线)第09讲 空间向量的应用 -【暑假自学课】2022年新高二数学暑假精品课(人教版2019必修第二册+选择性必修第一册)江苏省仪征市精诚高级中学2021-2022学年高二年级5月月考数学试题
名校
2 . 如图所示,已知长方体
中,
,
为
的中点,将
沿
折起,使得
.
![](https://img.xkw.com/dksih/QBM/2017/3/31/1655498603372544/1655671527243776/STEM/eedf1d77f8c146b3be95190bb8c18d65.png?resizew=531)
(1)求证:平面
平面
;
(2)是否存在满足
的点
,使得二面角
为大小为
?若存在,求出相应的实数
;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/100af11e6cb83b56437f2db7dadeb9f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e1e88b36ff71fe69c07bade0f95f1ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/804c0e2a375b5f4ff1c420532968efc3.png)
![](https://img.xkw.com/dksih/QBM/2017/3/31/1655498603372544/1655671527243776/STEM/eedf1d77f8c146b3be95190bb8c18d65.png?resizew=531)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bb5012f6c70a1e98d682b6d021fadd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0760712e3e2ea02b755b751e760d0c55.png)
(2)是否存在满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eaac8d2b8d350312c425b4f0dc5b8cd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a5266895d3c1fcb350a745bc779433b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9955b5aebb73cd84447e8541f901ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
您最近一年使用:0次
2017-03-31更新
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1377次组卷
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4卷引用:河南省息县第一高级中学2017届高三下学期第二次阶段测试理数试题