Once you have successfully brought the xprism3 window (Figure 3) up in your screen, the next logical step would be to plot something in the window. First you must select the Plot button on the left of the window. There are two ways of plotting a function. One is to use a file already made and use the Input File button. The other option is to create the function during the xprism3 session using the Input Function button.

Ok, so you have chosen to input a file you already have instead of typing a new one in. A good solid choice if you are going to be working with the same functions more than once. So you have clicked on the Input File button and brought up another window (Figure 4) which you must fill. I inputted a file called `test2.text` from my xprism3 directory. Note that you must put in the entire path name in the Filename box. Khoros is working from its own home directory, not yours. ` test2.text` contains the following information:

``` f(x,y) = sin(x)*cos(y) + x**2 x=(-pi,3.14,40) y=(-pi,3.14,40) ```

The correct syntax to use for the mathematical symbols is available in the Help box in the Input Function window. The `x=` and `y=` parentheses contain the left endpoint, the right endpoint, and the number of points in between, respectively. Since the text file already has the Points to Be Displayed information in it, I ignored that section of the window. For Plot Type, I chose my favorite, which is Color Mesh. I skipped the sections above the Plot Type since they have to do with Raw Data Files, and my data file is a function. Since I am done, then I click on the bottom button, Plot File. You may change your mind about the Plot Type and click on Plot File again. Xprism3 will draw the plots on top of each other, with the plot legends below. You may use the Hide option to just look at one at a time. Figure 5 shows the plot of `test2.text` using the Color Mesh option.

Figure 5 -- Plot of sin(x)·cos(y) + x²

To create functions during the xprism3 session, you must choose the Input Function option. The window will then change to something similar to Figure 6. If you have made this choice you must enter in a function in the box marked Function f(x, y)=. The Help box below will help you with the required syntax. Using the wrong syntax, the function I entered was

sin(x²) -2cos(y²) -x³y³

Please notice that I could not have entered the function in that form into the box and do not try to cut and paste it in there. Another rule to remember is that the function must be in terms of x and y. You have the option in this window to change the x and y parameters, but make sure that the function exists for those values. At the bottom of the window, you may select a Plot Type. Since xprism3 will graph up to 20 different graphs at once, you may try each of these, but I do not recommend it. Xprism3 will graph them on top of each other, making clarity impossible. I have chosen Color Mesh (which I will always do if given any freedom of choice). Once your selection is made, click on the Plot Function button and your graph will appear in the main xprism3 window. Figure 7 below is the result of the choices made in Figure 6. It should look quite familiar.

Figure 7 -- Plot of sin(x²)-2cos(y²)-x³y³