# What is the range of the function y = sec x?

Since $y = \sec x = \frac{1}{\cos} x$ and since the range of the function $y = \cos x$ is $\left[- 1 , 1\right]$, than the range of the function $y = \sec x$ is $\left(- \infty , 1\right] \cup \left[1 , + \infty\right)$.