Let $P$ and $Q$ be polynomials.

Find $\displaystyle \lim_{x \to \infty} \frac{P(x)}{Q(x)}$

if the degree of $P$ is (a) less than the degree of $Q$, and (b) greater than the degree of $Q$. If the answer is infinite, enter "I" below.

(a)
(b)