Pascal's Rule

A derivation of Pascal's Rule (aka, Pascal's Identity, or Pascal's Formula). This will come in handy in the upcoming proof of the Binomial Theorem, leading (eventually) to the Basel Problem.

The Binomial Coefficient is derived here: https://youtu.be/jbDQltyvFzA ... https://www.youtube.com/watch?v=USFEGKRVKrY