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[数列] 数列不等式(题目不知是否有错)

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等待hxh Posted 2014-4-16 17:07 |Read mode
6.jpg (一个自主招生讲义上的题,不知题目是否有问题,感觉数字不凑巧,不好放缩)

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kuing Posted 2014-4-16 19:27
右边真难看……果断没兴趣……

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realnumber Posted 2014-4-16 19:54
很难看,非得解的话,先数学归纳法?

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isee Posted 2014-4-16 21:32
移两项到左边,看起来就有点欧拉常数的感觉

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战巡 Posted 2014-4-16 23:43
Last edited by 战巡 2014-4-17 10:22回复 1# 等待hxh


之前看错了函数,重新算过
有:
\[\gamma+\frac{1}{2(n+1)}-\frac{1}{12(n+1)^2}<1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{n+1}-\ln(n+1)<\gamma+\frac{1}{2(n+1)}\]

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isee Posted 2014-4-16 23:52
回复 5# 战巡


    我好sha啊,我始终想,向回缩,就没想到小于欧拉常数呢,哈哈;


    看透的,推广也来了~

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 Author| 等待hxh Posted 2014-4-17 08:49
回复 5# 战巡
欧拉常数是下界,所以应该是大于欧拉常数,而不是小于它,你不等号搞反了

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