Answer
See graph, domain $\{x|x\ne \frac{2k\pi+\pi}{4}\}$ (k is an integer), range $(-\infty,-4]\cup[4,\infty)$.
Work Step by Step
1. See graph for $y=4sec(2x)$.
2. We can determine the domain $\{x|x\ne \frac{2k\pi+\pi}{4}\}$ (k is an integer), range $(-\infty,-4]\cup[4,\infty)$.