This graphing utility uses the Mathematica kernel to produce its images. Therefore, any functions that are in Mathematica are legal here. If you haven't used Mathematica before, there are a few things to know: Most functions start with a capital letter and place brackets around their arguements. So Sqrt[x] is the squareroot of x, and ArcSin[y] is the inverse sin of y. Multiplication can be indicated by a space or an asterisk (*). This means that x*y=x y. However, xy would be undefined. Constants also begin with capital letters, like Pi, E, or I. The natural logarithm (base E) is Log[x], while Log[b,x] is the logarithm with base b of x. i.e. Log[x]=Log[E,x] Brackets ([]) are reserved for functions and their options. To override Mathematica's order of operations, you must use parenthesese (()). The curly braces ({}) are reserved for lists. In Mathematica, you do not have to type the ten in scientific notation. For example, 3.4*10^3=3.4*^3=3400. If you would like to have a constant in your expression, use the letter a. For purposes of coloring, a is given a value of one, but it is shown as a symbol in all formula output. Be careful: while a*x can be represented as a x, it is different than ax, which is undefined. If you make an error in typing in your graph, it will be reset so that {x,y,z}={0,0,0} for all values of x and y (or u and v). If you make an error typing in the range of variables of your graph, they will be changed to -1 or 1, or otherwise modified. In the image coloring, red is positive, while blue is negative. Green is zero. To show the images, this page uses a java applet available on the web. There are several ways to interact with the applet: Drag with the left mouse button to rotate the image. Release the mouse button while dragging to spin the image. While holding the shift key: drag up to shrink the image, down to enlarge, right to rotate the image clockwise, and left to rotate the image counter-clockwise. Drag down with the right mouse button to remove sections of the image. This allows you to view inside solid objects if needed. To replace the sections, drag up. Press the s key to split the image into two images that can be viewed stereoscopically. Stare through the image to see a three dimensional renderring. Press the s key again to reverse the images, so that you cross your eyes to see it. Press the s key one last time to return the image to normal. While holding down the control key, drag the mouse to change the stereoscoped images.