Saturday, 26 November 2016

calculus - Show that $ lim_{n rightarrow infty} frac{n!}{2^{n}} = infty $

Show that $ \lim_{n \rightarrow \infty} \frac{n!}{2^{n}} = \infty $



I know what happens intuitively....



$n!$ grows a lot faster than $2^{n}$ which implies that the limit goes to infinity, but that's not the focus here.



I'm asked to show this algebraically and use the definition for a limit of a sequence.



"Given an $\epsilon>0$ , how large must $n$ be in order for $\frac{n!}{2^{n}}$ to be greater than this $\epsilon$ ?"




My teacher recommends using an inequality to prove it but I'm feeling completely lost...

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