Does anyone want to compare answers for the problem set?

This weekend I worked on that problem we were doing in class friday. Let me say, pretty challenging! Kind of cool though. You really had to know the definition of a derivative, that its the slope, so its equal to (y1-y2)/(x1-x2). It was fun, but really hard. I think a problem like that is better to do in a group, so we can bounce ideas off each other. It's a bit much to do by urself. I probably couldn't have done it if we hadn't started in class. Anyway, I think I got an answer.