If $ f (x) = sin ^ 4 (6x) + cos ^ 4 (6x) $ is a sine wave, look for amplitude, phase, and period.

Yes $ f (x) = sin ^ 4 (6x) + cos ^ 4 (6x) $ is a sine wave, find the amplitude, phase and period.

I do not know how to work with $ sin ^ $ 4 and $ cos ^ 4 $I tried to use the formula, but it does not work because of the $ 4 $e degree. Allusions?