Question

If the period of the function

$2\cos \frac{1}{3}(x-\pi )$ is k$\pi$, then k is

Answer 1

We know period of $k\cos (ax+b)$ is $\frac{2\pi }{|a|}$

Hence period of $2\cos \frac{1}{3}(x-\pi )$ is $\frac{2\pi }{1/3}=6\pi$