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解题方法
1 . 为弘扬中华民族优秀传统文化,某学校组织了《诵经典,获新知》的演讲比赛,本次比赛的冠军奖杯由一个铜球和一个托盘组成,如图①,已知球的体积为
,托盘由边长为4的正三角形铜片沿各边中点的连线垂直向上折叠而成,如图②.有下列四个结论:
①经过三个顶点A,B,C的球的截面圆的面积为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9955b5aebb73cd84447e8541f901ac.png)
②异面直线AD与CF所成的角的余弦值为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6503ca085e3ca5f2ba723b0dd66e210b.png)
③直线AD与平面DEF所成的角为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
④球离球托底面DEF的最小距离为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db8de9b18c298b61e085bd0160750f11.png)
![](https://img.xkw.com/dksih/QBM/2022/5/4/2971998917713920/2973137296678912/STEM/a80417fa-93d7-4818-a1cc-0d67aa7655ae.png?resizew=546)
其中正确的命题是__________
请将正确命题的序号都填上
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4966e5af166b69a0a38a98abf555b6b.png)
①经过三个顶点A,B,C的球的截面圆的面积为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9955b5aebb73cd84447e8541f901ac.png)
②异面直线AD与CF所成的角的余弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6503ca085e3ca5f2ba723b0dd66e210b.png)
③直线AD与平面DEF所成的角为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
④球离球托底面DEF的最小距离为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db8de9b18c298b61e085bd0160750f11.png)
![](https://img.xkw.com/dksih/QBM/2022/5/4/2971998917713920/2973137296678912/STEM/a80417fa-93d7-4818-a1cc-0d67aa7655ae.png?resizew=546)
其中正确的命题是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a301324443eb93b467134a86890dd9ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
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