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What is value of $\displaystyle\lim_{n\to+\infty} n^{-2}e^{(\log(n))^a}$, where $a > 1$? I tried l'Hospital's rule but it gets complicated.

2 Answers 2

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$n^{-2}e^{(\log(n))^a} = e^{(\log(n))^a - 2 \log(n)}$. If $a$ is a constant greater than $1$ then $(\log(n))^a$ will dominate compared to $2 \log(n)$, so this expression will also go to infinity as $n$ goes to infinity.

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Hint: Consider taking the logarithm.

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    @quartz: You are welcome!2012-04-17