This is LaTeX code:
[latex]
\frac{e^n}{2} - \frac{e^{-n}}{2}+th(n)\leq \frac{e^n}{2} - \frac{e^{-n}}{2}+1 \leq \frac{e^n}{2} + \frac{e^{n}}{2}= e^n
[/latex]