Mathematics

Problem

The general solution of the equation

\cos 3x = 0

is a)

x = \dfrac{\pi}{6} + n\pi,\; n\in\mathbb{Z}

x = \dfrac{\pi}{2} + n\pi,\; n\in\mathbb{Z}

x = \dfrac{\pi}{6} + \dfrac{n\pi}{3},\; n\in\mathbb{Z}

x = \dfrac{\pi}{6} + \dfrac{2n\pi}{3},\; n\in\mathbb{Z}