Answer
see graph.
Work Step by Step
Given $y=\frac{1}{2}cos(\frac{1}{2}x-\frac{\pi}{4})=\frac{1}{2}cos[\frac{1}{2}(x-\frac{\pi}{2})]$, we can identify its amplitude as $\frac{1}{2}$, period as $p=\frac{2\pi}{1/2}=4\pi$, and phase shift as $\frac{\pi}{2}$ to the right, see graph.
