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[分析/方程] n趋近于无穷大时$x_n$收敛,求x范围

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abababa posted 2016-9-2 18:06 |Read mode
已知$x>0$,定义$x_1=x,x_2=x^x,x_3=x^{x^x}$,等等,若当$n\to\infty$时$x_n$收敛,求$x$的范围。
我求出来当$1\le x\le e^{\frac{1}{e}}$时收敛,当$0<x<1$时不知道它是不是收敛的。

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kuing posted 2016-9-2 18:51

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original poster abababa posted 2016-9-2 19:11
回复 2# kuing

谢谢。两个子列分别收敛到不同的极限,要想整个数列都收敛就必须这两个极限相等,然后必须$x^{x^y}=y$只有一个根。
看了链接里的链接,原来这个问题还有很多专门的讨论啊,看来挺深奥的。

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