Chapter 4: Applications of Derivatives - Section 4.3 - Monotonic Functions and the First Derivative Test - Exercises 4.3 - Page 203: 15

(a) Increasing on $(-2,0)\cup(2, 4)$ , Decreasing on $(-4, -2) \cup (0,2)$ (b) Absolute maximum at $(-4,2)$. Absolute minimum at $(2, -3)$. local maximum at $(0,1)$ and $(4, -1)$. local minimum at $(-2,0)$.

See image below.