Answer
(a) maximum at $(0,1)$
(b) minimum at $(-\pi,-1)$ and $(\pi,-1)$
Work Step by Step
(a) We see from the graph that $f$ has a local maximum at $(0,1)$
(b) We see from the graph that $f$ has a local minimum at $(-\pi,-1)$ and $(\pi,-1)$
Recall, a local minimum occurs when the slope changes from negative to positive while a local maximum occurs when the slope changes from positive to negative.
