This article had a brutal leap from being aimed at someone with barely any understanding of maths (complete with friendly emojis) to use of cost functions (without any explanation) and associated code. It's bit like the "how to draw an owl" meme. A good article on linear regression, in my opinion, would break it down into three steps: 1. Spend a bit of time looking at cost functions. In principle linear regression is…
Personally, I find linear regression makes more sense from an orthogonality of sub-spaces perspective. That the same solution can be derived as the optimum of some cost function is neat though.