EDIT: At 2:05 - forgot to mention that, |r| must be less than 1 only when n approaches infinity!
In this video, we take a look a few common summation formulas and probability distributions, as well as some properties of expectation.
Notes: https://www.dropbox.com/s/1q2npjc3h5blmvs/prob-stats-csc263.pdf?dl=0
