# Question #c2359

Mar 5, 2015

Find the angles first ($3 x$), then find $x$.

The cosine of some angle is to be $\frac{\sqrt{3}}{2}$.

The angles with that cosine are all of the form: $\frac{\pi}{6} + 2 \pi k$ or $- \frac{\pi}{6} + 2 \pi k$ for integer $k$.

This tells us that $3 x$ must be $\frac{\pi}{6} + 2 \pi k$ or $- \frac{\pi}{6} + 2 \pi k$ for integer $k$.

Solve the two equations

$3 x = \frac{\pi}{6} + 2 \pi k$ and $3 x = - \frac{\pi}{6} + 2 \pi k$ for $x$.