Answer
$$x=\frac{\pi }{2}+2\pi n,\:x=\frac{3\pi }{2}+2\pi n$$
Work Step by Step
We solve the equation using the properties of trigonometric functions. Note, there is a general solution since trigonometric identities go up and down and this can pass through a given value of y many times. Solving this, we find:
$$\cos \left(x\right)\left(\sin \left(x\right)-3\right)=0 \\ \cos \left(x\right)=0\quad \mathrm{or}\quad \sin \left(x\right)-3=0 \\ x=\frac{\pi }{2}+2\pi n,\:x=\frac{3\pi }{2}+2\pi n$$
