Q: If X is domain and Y is range, what is Z? This is a really small stupid question, but I'm currently self-teaching myself Multivariable Calculus, and I'm just curious if there is a term for this. I did a small google search and didn't find anything, so I would appreciate anything thanks!
Thanks!

A: In single-variable calculus, X is the domain and Y is the range. In 3-D coordinates, X and Y are the domain (i.e., $\mathbb{R}^2$) and then Z is the range.
