NOTICE: This lesson (alongside its brief continuation next week) is the single most math-heavy online lesson in CS 159. The only math from this lesson that you'll be expected to be able to do on an exam is the math on the third page ("A Biological Inspiration"). For all other pages, we want you to be generally familiar with the mathematical concepts covered, but will not ask you to actually apply the formulas on a homework or exam question. So, while you should take the lesson seriously as always, please do not get lost in the details of figuring out each and every equation. And if anything is just too confusing to follow at even a high level, don't hesitate to let us know in the feedback.