Chapter 4 - Section 4.1 - Maximum and Minimum Values - 4.1 Exercises - Page 283: 22

The absolute maximum is $f(0) = 1$ The absolute minimum is $f(-\pi) = f(\pi) = -1$ The local maximum is $f(0) = 1$ The local minima are $f(-\pi) = f(\pi) = -1$

$f(t) = cos~t,~~~~~-\frac{3\pi}{2} \leq t \leq \frac{3\pi}{2}$ The absolute maximum is $f(0) = 1$ The absolute minimum is $f(-\pi) = f(\pi) = -1$ The local maximum is $f(0) = 1$ The local minima are $f(-\pi) = f(\pi) = -1$