Answer
See graph, domain $\{x| x\ne k\pi+\frac{\pi}{2}\}$ (k is an integer), range $\{y|y\le-2\ or\ y\ge2\}$.
Work Step by Step
1. See graph for $y=2sec(x)$.
2. We can identify the domain $\{x| x\ne k\pi+\frac{\pi}{2}\}$ (k is an integer), range $\{y|y\le-2\ or\ y\ge2\}$.