Evaluate the following limits.

(a) $$\lim_{ x \to \infty } \frac{ 3 }{ e^x + 1 } =$$

(b) $$\lim_{ x \to -\infty } \frac{ 3 }{ e^x + 1 } =$$
[NOTE: If needed, enter INF for $\infty$ and MINF for $-\infty$.]