Answer
$|A|=2$, $p=\frac{2\pi}{2}=\pi $, $\phi=\frac{\pi}{4}$.
See graph.
Work Step by Step
Step 1. Given $y=-2cos(2x-\frac{\pi}{2})=-2cos[2(x-\frac{\pi}{4})]$, we can find the amplitude $|A|=2$, period $p=\frac{2\pi}{2}=\pi $, and phase shift $\phi=\frac{\pi}{4}$.
Step 2. See graph.
