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[函数] 求一个绝对值函数的最小值

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lemondian posted 2019-5-19 20:27 |Read mode
求函数$f(x)=|x-1|+|2x-1|+|3x-1|+\cdots +|2019x-1|$的最小值。

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realnumber posted 2019-5-19 20:44
$y=\abs{x-a}+\abs{x-b},a<b$,在$x\in [a,b]$时最小
$y=\abs{x-a}+\abs{x-b}+\abs{x-c},a<b<c$,在$x=b$时最小
更一般也如此
$y=\abs{x-1}+\abs{x-\frac{1}{2}}+\abs{x-\frac{1}{2}}+\abs{x-\frac{1}{3}}+\abs{x-\frac{1}{3}}+\abs{x-\frac{1}{3}}+\cdots $

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original poster lemondian posted 2019-5-19 21:14
回复 2# realnumber
我好象在那见过这类题,但不记得了。
好象有更一般的情形,分类讨论什么的

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色k posted 2019-5-19 21:47
回复 3# lemondian

看《憋间》第1期何版主写的那篇

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original poster lemondian posted 2019-5-20 15:34
回复 4# 色k
这些结论有没有证明的呢?

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色k posted 2019-5-20 16:07
回复 5# lemondian

你觉得文中写的不是一个证明???

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