My start: Say $\lim(t_n)=b$ and let $\epsilon>0$. Then there exists $N$ such that $n>N$ implies $|t_n-b|<\epsilon$.
or should I say:
Let $a>0$. Then there exists $N$ such that $n>N$ implies $|t_n-b|<a$.
Am I going in the right direction? Any tips of where to go from here would be helpful.