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[几何] 立几河马题

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力工 Posted 2018-5-16 14:46 |Read mode
题立几.png 好棘手,表示那个转太难

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kuing Posted 2018-5-16 15:09
请码代码,我不想找放大镜

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dahool Posted 2018-5-16 15:27
回复 2# kuing

棱长为$36$的正四面体$A-BCD$的内切球上有一动点$M$,则$MB+\frac{1}{3}MC$的最小值为___________.

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kuing Posted 2018-5-16 16:17
这四面体显然是吓人的,因为很明显取最值的点必在平面 OBC 上,于是变成平面问题,然后再用阿氏圆套路如无意外就OK了

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realnumber Posted 2018-5-16 18:52
标题河马什么意思?

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isee Posted 2018-5-16 19:49
回复 5# realnumber


要么是多余的,要么是粤语。。。。。

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色k Posted 2018-5-16 20:28
回复 6# isee

不会是粤语

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kuing Posted 2018-5-16 20:54
回复 5# realnumber

可能是“将军饮马问题”的另一种称呼?

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isee Posted 2018-5-16 20:55
回复 8# kuing

汗,这么一看还真是 将军饮马 简化 为 河与马 了

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