名校
解题方法
1 . 如图长方体
中,
,
,过点
的平面
与此长方体的面相交,交线围成一个边长为5的菱形.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/2/9faeedd4-0f73-4dce-b40a-a65ae76fd492.png?resizew=108)
(1)在图中画出这个菱形(说明画法,但不必证明);
(2)若平面
与
的交点为F,求直线CF与平面
所成的角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b37750daa8ba3b3fe3e9e2092f81c848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac5e1093a147c521c5e8d0d5e266db54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/2/9faeedd4-0f73-4dce-b40a-a65ae76fd492.png?resizew=108)
(1)在图中画出这个菱形(说明画法,但不必证明);
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
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