Prove that for any integer $\displaystyle n\geq 2 $
$\displaystyle \frac{1}{2}+\frac{1}{3}+ ... +\frac{1}{n} \leq log(n) \leq 1+ \frac{1}{2}+\frac{1}{3}+ ... +\frac{1}{n-1}$.
I am not sure where to start on this so maybe someone could give me a hint on what theorem(s) to use/where to start? thanks!