解题方法
1 . 正多面体也称柏拉图立体(被誉为最有规律的立体结构)是所有面都只由一种正多边形构成的多面体(各面都是全等的正多边形).数学家已经证明世界上只存在五种柏拉图立体,即正四面体、正六面体、正八面体、正十二面体、正二十面体.已知一个正八面体
的棱长都是2(如图),
、
分别为
、
的中点,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78aa2d427fb896e5e192c2032a62b81b.png)
______ .若
,过点
的直线分别交直线
于
两点,设
(其中
均为正数),则
的最小值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78aa2d427fb896e5e192c2032a62b81b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e43856d85d8b02b04c384e861b17b43e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/920d660d739cccff6b64c90125bafa64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6670479a0083dd2dfd5ad55b47b1ab6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28fb003b390ebb911cba4a49f96043da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0877194ab8760f54c35527177b03ff93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b88ea271b3352d75008832f129d39dc0.png)
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