Answer
(a) local maximum at $x=\frac{\pi}{2}$; local maximum value is $1$
(b) local minimum at $x=-\frac{\pi}{2}$; local minimum value is $-1$
Work Step by Step
Based on the give graph:
(a) The number at which f has a local maximum is $x=\frac{\pi}{2}$ and the local maximum value is $1$
(b) The number at which f has a local minimum is $x=-\frac{\pi}{2}$ and the local minimum values is $-1$
