Find the limit (or prove it doesn't exist) for $(s_n)$ where $s_n = \cos(n)$. Let $n$ be in radians. (Hint: look at $\sin(n + 2) - \sin(n)$ and $\cos(n + 2) - \cos(n)$.)
From Calculus, I know that this limit doesn't exist. I'm having an issue figuring out how to give a proof using the hint we were provided.