名校
解题方法
1 . 如图,在棱长为
的正方体
中,
为棱
的中点,
,
分别是棱
,
上的动点(不与顶点重合).
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/7230b3f9-55f8-4ce6-9945-25efc93a341a.png?resizew=180)
(1)作出平面
与平面
的交线(要求写出作图过程),并证明:若平面
平面
,则
;
(2)若
,
均为其所在棱的中点,求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/7230b3f9-55f8-4ce6-9945-25efc93a341a.png?resizew=180)
(1)作出平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abb06405623edb5c9d5f7350d79dc76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee8b5a6dbcf05f572f83f51abf7d668c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ecd2020a3f7767e54ab47e640399a6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48d47e5be88e89d0d042c56d2d6942b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6c6b8443e6525024643e9d87c45640f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48d47e5be88e89d0d042c56d2d6942b0.png)
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