# How do you find the period of y=sin(-1/3x)?

Period of$y = \sin \left(\frac{- x}{3}\right)$
The period of $\sin \left(\frac{- x}{3}\right)$ is ( 6pi.), because:
$\sin \left(- \frac{x}{3}\right) = - \sin \left(\frac{x}{3} + 2 \pi\right) = - \sin \left[\frac{1}{3} \left(x + 6 \pi\right)\right]$
Therefor, the period of $\sin \left(- \frac{x}{3}\right)$ is $6 \pi .$