You can use the CRC Handbook of Math Tables to give you an idea of some of the things you can do. CRC is short for the Chemical Rubber Company. You might also try getting a Polar Coordinates graphing program so that the children can enter the formulas and see the results. I don't have a program handy, but recall writing one that was about 20 lines of BASIC code.
michael ================================================================================ I am looking for some resources for Polar Graphing that would be appropriate for use with 4th grade students. I would appreciate any suggestions.