# What is the period of y=cos x?

The period of $y = \cos \left(x\right)$ is $2 \pi$
$p e r i o d = \omega = \frac{2 \pi}{B}$, where $B$ is the coefficient of the $x$ term.
$p e r i o d = \omega = \frac{2 \pi}{1} = 2 \pi$