名校
1 . 如图在三棱锥
中,点
,
,
,
分别为相应棱的中点,
![](https://img.xkw.com/dksih/QBM/2020/10/30/2582361868599296/2582829679149056/STEM/d8f69c07-c44e-4b6f-920b-38a2af2fb426.png?resizew=224)
(1)求证:四边形
为平行四边形.
(2)若
,
,求异面直线
与
所成的夹角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.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/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://img.xkw.com/dksih/QBM/2020/10/30/2582361868599296/2582829679149056/STEM/d8f69c07-c44e-4b6f-920b-38a2af2fb426.png?resizew=224)
(1)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aba63d391602d0798a1875da35fef40d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c092ad8e71db52e8966993beebb50ee3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1826cf174638e4b20141069fa1f3c385.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
您最近一年使用:0次
2020-10-31更新
|
362次组卷
|
2卷引用:新疆皮山县高级中学2022-2023学年高一下学期期末考试数学试题
2 . 已知在长方体
中,
分别是
的中点,
.
![](https://img.xkw.com/dksih/QBM/2016/10/6/1573055573901312/1573055579578368/STEM/6467c61bd80b4195aff68f701d99fb97.png)
(I)证明:
∥平面
;
(II)求直线
与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8456cee87c4e22351affc28f3a73a0f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c88339e64acf5f1efeaea8e9c856ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4ef611321cd8b655f4307fa04704ee5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f3442496f4eb1901fa9e226e626268d.png)
![](https://img.xkw.com/dksih/QBM/2016/10/6/1573055573901312/1573055579578368/STEM/6467c61bd80b4195aff68f701d99fb97.png)
(I)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
(II)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/193b5b41994c2a4dfa5bb0bc984061cc.png)
您最近一年使用:0次
2016-12-04更新
|
379次组卷
|
2卷引用:2015-2016新疆哈密地区二中高二下期末考试理科数学卷
3 . 如图是正方体的平面展开图,在这个正方体中,正确的命题是
![](https://img.xkw.com/dksih/QBM/2019/2/26/2149120719814656/2153938962792449/STEM/be72ed339bd74d3db8fabdae031867e8.png?resizew=155)
![](https://img.xkw.com/dksih/QBM/2019/2/26/2149120719814656/2153938962792449/STEM/be72ed339bd74d3db8fabdae031867e8.png?resizew=155)
A.BD与CF成60°角 | B.BD与EF成60°角 | C.AB与CD成60°角 | D.AB与EF成60°角 |
您最近一年使用:0次
2016-12-04更新
|
542次组卷
|
4卷引用:新疆乌鲁木齐市第八中学2018-2019学年高一下学期期末考试数学试题