TeX source:

\lim\limits_{t \rightarrow \infty} h^{\prime}(t)=\lim\limits_{t \rightarrow \infty} \frac{(1+t) \cos (t)-\sin (t)}{(1+t)^{2}}=\lim\limits_{t \rightarrow \infty}\left\{\frac{\cos (t)}{1+t}-\frac{\sin (t)}{(1+t)^{2}}\right\}=0 \mathbf{f t} / \mathbf{s e c}