Calculus+and+Riemann+Sums

I have found a wonderful TI-83/84 graphing calculator program entitled "RIEMANN" which allows you to input a function, define the intervals over which you would like to find the area underneath the curve, determine the number of rectangles to be drawn, and then choose among left, right, and midpoint sums. Then the graph of the function with the desired rectangles (left, right, or midpoint) is displayed---so much easier than trying to illustrate all these by hand. Finally, a screen will appear with the indicated sum. The program provides a wonderful visual for seeing the inscribed and circumscribed rectangles and how as the number of rectangles increases, the area more closely resembles the area underneath the curve. It also allows students to visually appreciate the origin of the summation formula for finding Riemann sums using left and right endpoints, etc. I have been using this to introduce the concept of Riemann sums for years. The visual effects are wonderful. If you are interested in this program, let me know when I visit your schools and I will download it onto your calculator. (I cannot take credit for writing the program and wish I knew to whom to give the credit, but it is one of those things that has been passed along to me and I will gladly pass it along to you.)