The notes above are from a couple days ago when Simon was trying to explain to me, where the formula for calculating similarity s = 1/1+c comes from. He linked it to the Euclidean distance formula and explained how Eucledean distance is related to the Pythagorean theorem.
The similarity formula comes from the Nearest Neighbour Recommendation Engine Coding Challenge by Daniel Shiffman that Simon was doing. the coding challenge was about creating a movie recommendation engine using the a “nearest neighbor” algorithm and thus calculating a similarity score between two data points.
Here Simon explains how that code works: