Answer
A: $ f(0)=1 $
B: $ f(-\frac{\pi}{4})= 0 $
C: $ f(\frac{\pi}{3})= -\frac{1}{2} $
D: $ f(\pi)= 1 $
Work Step by Step
A:
$ f(0)=\cos{(2\times0)} $
$ f(0)=\cos{0} $
$ f(0)=1 $
B:
$ f(-\frac{\pi}{4})= cos{(2\times (-\frac{\pi}{4}))} $
$ f(-\frac{\pi}{4})= cos{(-\frac{\pi}{2})} $
$ f(-\frac{\pi}{4})= 0 $
C:
$ f(\frac{\pi}{3})= cos{(2\times \frac{\pi}{3})} $
$ f(\frac{\pi}{3})= cos{\frac{2\pi}{3}} $
$ f(\frac{\pi}{3})= -\frac{1}{2} $
D:
$ f(\pi)= \cos{(2\times \pi)} $
$ f(\pi)= \cos{2\pi} $
$ f(\pi)= 1 $
