This demo shows some contours for the function f(x,y)= x2 - y2. The contours consist of contour curves f(x,y) = c, and you can view them on the function graph in the "Function Graph: f(x,y)" window.

In the "Domain: f(x,y)" window, we show the contour curves projected down into the xy-plane without actually displaying the function graph. This is called a "contour map", and it will prove to be very useful to look at in analyzing function graphs of functions f depending on more than two variables.

Actually, it is quite possible to view contours without being able to look at the graph itself, and this can already give a lot of information about the function. (Check out the corresponding lab for three dimensions!!)