The syntax for the input is essentially copied from Maple. The following examples are illustrative:
tan(x-x*cos(Pi*x))There are a few more options as well: you may zoom in on a region by holding the Control key and clicking on the graph. Conversely, you may zoom out by holding the Shift key and clicking. Where you click becomes the new center of the graph. You may translate the graph by holding down the Alt key and dragging the mouse around the graphing area.
If something goes wrong, please email me with a description of what you did and what happened.