Answer
a.)$\frac{\sqrt 3}{2}$
b.)$\frac{\sqrt 3}{2}$
Work Step by Step
a.)cos $\frac{\pi}{6}$ corresponds to x value.
cos $\frac{\pi}{6}$ = $\frac{\sqrt 3}{2}$.
b.)Cosine is an even function, so cos(-t) = cos t.
cos-$\frac{\pi}{6}$ = cos$\frac{\pi}{6}$ = $\frac{\sqrt 3}{2}$
