Limits to infinity of a factorial function: $\lim_{n\to\infty}\frac{n!}{n^{n/2}}$ How can this limit to infinity be solved? I've tried with d'Alembert but it just keeps coming up with the wrong answer.
$$\lim\limits_{n\to\infty}\frac{n!}{n^{n/2}}$$
I might have a problem in simplifying factorial numbers. 
Thank you in advance. 

$$n!\geq\left (\frac{n}{4}\right )^{3n/4}\\\lim_{n\to\infty}\frac{\left (\frac{n}{4}\right )^{3n/4}}{n^{n/2}}=\lim_{n\to\infty}\frac{n^{n/4}}{4^{3n/4}}=\lim_{n\to \infty}\left(\frac{n}{64}\right)^{n/4}=\infty$$
The inequality comes since $4n!=1\cdots \underbrace{n\cdots 4n}_{3n}\geq \underbrace{n\cdots n}_{3n}=n^{3n}$
