$$\lim_{n\to\infty} a_n = \lim_{n\to\infty}\frac {3+\cos(n\pi/2)}{2+\sin(n\pi/2)} $$
I don't understand how to calculate trigonometric limits to infinity, therefore, I am lost.
Thanks for the tips. I understand what you want to say but i still don't know how i should present it on Paper.
HINT: Note that $a_{4n}=2$ and $a_{4n+2}=1$. What does this tell you about the limit of $a_n$ as $n\to\infty$?