Solve using trig identity?

Is it possible to solve the following using trigonometry identities?

sqrt((-3+4cos(w))^2)

Alternatively

sqrt((1-4/3cos(w))^2)

I m trying to simplify it so that i can use something like sin(w) = 1-cos(w)^2. I m trying to solve for the frequency response. I have tried a few times to simplify this but not sure how to. Can i just leave it the way it is for frequency response?