Answer
See graph, domain $\{x|x\ne \frac{k\pi}{2} \}$ (where $k$ is an odd integer), range $(-\infty,-2]U[2\infty)$.
Work Step by Step
Step 1. See graph for $y=2sec(x)$.
Step 2. Based on the graph, we can determine the domain $\{x|x\ne \frac{k\pi}{2} \}$ (where $k$ is an odd integer), range $(-\infty,-2]U[2\infty)$.