1 . 在正方体
中,已知
为
的中点.
![](https://img.xkw.com/dksih/QBM/2016/7/22/1572937843916800/1572937850101760/STEM/922b8fe71126494cba45873ae7d38fd8.png)
(1)求证:直线
;
(2)求直线
与
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8456cee87c4e22351affc28f3a73a0f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://img.xkw.com/dksih/QBM/2016/7/22/1572937843916800/1572937850101760/STEM/922b8fe71126494cba45873ae7d38fd8.png)
(1)求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/575f6a78e86ca8df45c07d343a8552ad.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fe734023d4e70010a6b2cc3267cb86e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
您最近一年使用:0次
2 . 两条直线
与
的关系是
![](https://img.xkw.com/dksih/QBM/2016/7/22/1572937843916800/1572937849749504/STEM/a66dc448fb6e4e989769b7c0c911339e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcfc6b5b7ae63a330f0cd8593ee47338.png)
A.平行 | B.垂直 | C.相交且不垂直 | D.重合 |
您最近一年使用:0次
3 . 已知
是直线
上的动点,
、
是圆
的两条切线, 圆心为
,那么四边形
面积的最小值是
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701802496/STEM/43df952052e649348d5fd3cc848959e4.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701802496/STEM/69ed3da9bf0345af80ab35f93257ffce.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701802496/STEM/9bfe137bb6e044318ac914ab1ddcc56f.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701802496/STEM/bfb6d083dbf444acac4560996e74ed80.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701802496/STEM/303b15e2b5e14dbb94001fda3a1b175c.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701802496/STEM/f00b8f489d5042d48e35ebd44065a94f.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701802496/STEM/60ef570642af4be2ab979daf183bf594.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
4 . 已知三棱柱
的6个顶点都在球
的球面上,若
则球
的表面积为
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701745152/STEM/fd9ce500b7e24d76a1ff37dfd41b8382.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701745152/STEM/d6c6a8e14b13498f9360088975f5e5c6.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701745152/STEM/7d0615c2a56949a48c6be1a02f5fbf22.png)
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892695781376/1572892701745152/STEM/d6c6a8e14b13498f9360088975f5e5c6.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
5 . 一个几何体的顶点都在球面上,它们的正视图、侧视图、俯视图都是下图.图中圆内有一个以
圆心为中心边长为1的正方形.则这个四面体的外接球的表面积是
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892418416640/1572892423938048/STEM/1f08e081f8bc4ab6944caeffa0215a33.png)
圆心为中心边长为1的正方形.则这个四面体的外接球的表面积是
![](https://img.xkw.com/dksih/QBM/2016/7/5/1572892418416640/1572892423938048/STEM/1f08e081f8bc4ab6944caeffa0215a33.png)
A.2π | B.3π | C.4π | D.5π |
您最近一年使用:0次