Hello; I'm currently a high school student who is enrolled in an AP Calculus AB class; the section we're currently studying is approximation rules. Although the teacher was able to load everyone's calculator up with the TI-program that handles Right-hand, Left-hand, and Mid-point approximation rules, she didn't find a program that corresponded to the HP 50g. I tried searching the HP-calculator program site (http://www.hpcalc.org/) but I couldn't find anything that would be fitting. Could someone point me in the right direction? Are there other sites that also carry a large selection of HP calculator programs? Thanks!