名校
解题方法
1 . 如图,已知在四面体
中,
,
,
.
、
分别为
、
中点.
为
、
的公垂线;
(2)求空间内任一点
到四面体
四个顶点距离和的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e096f87473d0b6b6d531ba22e5a7c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c838e9a018189b92b1a56d57aa26389e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bf7c885153243a3f763c4c8e6268247.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(2)求空间内任一点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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解题方法
2 . 如图,在三棱锥
中,已知
平面ABC,
,
,D为PC上一点,且
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/16/596607b1-7bdb-44f4-b321-6c45cae4f8b5.png?resizew=179)
(1)求AC的长;
(2)若E为AC的中点,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83a04565a8ebaa111894b724b0ba266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e73929198cc43a209deb1ae9bc0841a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4125524caac016727c80d2722c5ba3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/16/596607b1-7bdb-44f4-b321-6c45cae4f8b5.png?resizew=179)
(1)求AC的长;
(2)若E为AC的中点,求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a879800a059ce741a99bb2c171f32afe.png)
您最近一年使用:0次