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[不等式] 一道困难的n元不等式

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dtscorpio Posted 2022-11-28 18:01 |Read mode
Last edited by hbghlyj 2025-3-21 00:23设实数 $a_1, a_2, \cdots, a_n$ 满足 $a_1^2+a_2^2+\cdots+a_n^2=1$.求证:
\[
\prod_{1 \leq i<j \leq n}\left(a_i-a_j\right) \leq \sqrt{\frac{2^2 \cdot 3^3 \cdots \cdot n^n}{(n(n-1))^{\frac{n(n-1)}{2}}}}
\]

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yao4015 Posted 2022-11-30 10:45
楼主能说下题目的出处吗?

$n=4$ 的情况,我得到过,见 forum.php?mod=viewthread&tid=6364&extra=

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 Author| dtscorpio Posted 2022-11-30 18:47
yao4015 发表于 2022-11-30 10:45
楼主能说下题目的出处吗?

$n=4$ 的情况,我得到过,见 https://kuing.cjhb.site/forum.php?mod= ...
微信小程序“数之谜”的题库-原创题-代数第33题,似乎是一位叫“most”的高手出的。

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hbghlyj Posted 2022-11-30 20:09
知乎问题:如何评价微信小程序数之谜?
问题描述:数之谜小程序由北京人大附中张端阳老师创建,包括各国各级数学奥林匹克竞赛题目,是张老师的心血之作

知乎问题:你心目中最欣赏的数学竞赛教练是谁?
明日方舟的回答:
...他把他这些年讲过的赛题全部整理在“数之谜”小程序里了

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hbghlyj Posted 2022-11-30 20:14

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