Difference between f(x) and f(x,y)? I recently started doing calculus and came across terms such as f(x) and f(x,y). What is the difference between them? Are they the same thing?

In higher-level calculus, functions have multiple variables plugged into them and are charted using $(x,y,z)$! For example, if you wanted to graph the height of your driveway, you could use $h(w,l)$ where $w$ is a point on the width and $l$ is a point on the length. Check out Wolfram|Alpha for more of that stuff. They'll even let you try graphing some of your own $x$-$y$-$z$ functions!
