Since it looks like you guys need some reminders on how to evaluate arithmetic and geometric series (from Ch. 1), here are two videos that I made that go over just that:
Evaluating an arithmetic series (5 minutes and 47 seconds long)
Evaluating a geometric series. In this video I made a small mistake in my oral explanation. Can you catch it? (It’s not enough to “mess you up.”) This video is 4 minutes and 38 seconds long.