a. Assuming that $\lim _{n \rightarrow \infty}\left(1 / n^{c}\right)=0$ if $c$ is any positive con-
$$\lim _{n \rightarrow \infty} \frac{\ln n}{n^{c}}=0$$
if $c$ is any positive constant.
b. Prove that $\lim _{n \rightarrow \infty}\left(1 / n^{c}\right)=0$ if $c$ is any positive constant. (Hint: If $\epsilon=0.001$ and $c=0.04,$ how large should $N$ be to ensure that $\left|1 / n^{c}-0\right|<\epsilon$ if $n>N ? )$