The following applet draws the surface z=f(x,y) for a \le x \le b and c \le y \le d. Simply enter the function f(x,y) and the values a, b, c and d.
The values a, b, c and d can be changed by simply typing a new value, such as "1.2345", "pi/2", "sqrt(5)+cos(3)", etc. You may also change these values by using the up/down arrow keys, dragging the corresponding point left or right, or dragging the corresponding line up or down. To move the center of the graph, simply drag any point to a new location. To label the x-axis in radians (i.e. multiples of pi), click on the graph and press "control-r". To switch back, simply press "control-r" again.
You can rotate the object about the center of the screen by dragging the mouse while holding down the SHIFT key.