An introduction to the magic of machine learning

We hear about machine learning a lot these days, and in fact it's all around us. It can sound kind of mysterious, or even scary, but it turns out that machine learning is just math. And to prove that it's just math, I will write this article the old-school way, with hand-written equations instead of code. If you prefer to learn by listening and watching, I posted a video that covers the content of this article here. To explain what machine learning is and how math makes it work, we will do a full walk-through of logistic regression, a fairly simple but fundamental model that is in some sense the building block of more complex models like neural networks.