Corrected due dates and typo

I corrected the due dates for problem #4 and project #2. I also corrected the typo in the numerical example we went over right at the end of today's lecture.

Please take time to think about what we covered today. I'll take time at the beginning of class on Friday to answer questions, if anyone can formulate one. Your question doesn't even have to seem coherent. I can probably figure out what's confusing you if you'll just ask.