Answer
Please see below.
Work Step by Step
Please note that a cosine function $y=A\cos (Bx-C)$ has amplitude $|A|$, period $\frac{2\pi }{B}$, and phase shift $\frac{C}{B}$.
So the function $y=4\cos (2x-\pi )$ has amplitude $|4|=4$, period $\frac{2\pi }{2 }=\pi $, and phase shift $\frac{\pi }{2}$.
