## Calculus (3rd Edition)

The domain is all real numbers. The range is $-1 \leq y \leq 1$
The function is valid for all values of t, because $cos (x)$ is a function that is valid for all x inputs. The maximum value that you can get out of the function $cos(x)$ is 1, and minimum is -1 (cosine function is a wave). Thus, the range spans from -1 to 1.