Linear Algebra. Polynoms. Interpolation. Least squares

In this part of lectures we will talk about simplest "ml models" -- polynoms. But alone polynoms is just some function, so we will also talk about Interpolation of them and will try to make ith with Least Squares method. Let's start from looking at magic: As we see we could interpolate our 2nd order polynom equation very precise(green line totaly cover red line). The only exception is periodic functions because polynom is not periodic. So what we can do with this thing?