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[组合] 正方形里放点

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Shiki posted 2019-5-26 12:38 |Read mode
Last edited by Shiki 2019-5-26 13:00有一边长为1的正方形$ABCD$,在其中有一百个点$P_i(i=1,2,3,•••100)$
$E,F,G,H$分别为边$AB,BC,CD,DA$中点.
定义
$d_1=\Sigma_{i=1}^{100}EP_i \\
d_2=\Sigma_{i=1}^{100}FP_i   \\
d_3=\Sigma_{i=1}^{100}GP_i  \\
d_4=\Sigma_{i=1}^{100}HP_i    \\
$
求证:$d_1,d_2,d_3,d_4$中至少有两个小于$81$
= =

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游客 posted 2019-5-26 14:45
Last edited by hbghlyj 2025-3-19 18:09对边中点配对
$d_1+d_3<50(\sqrt{5}+1)<162$.

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