Least squares and the normal equations

What it means to solve a system that has no solution, the projection that answers it, the normal equations $A^{T}A\hat{x} = A^{T}b$ and where they come from, the line of best fit as an instance of them, residuals and what they must satisfy, and the QR route that avoids forming $A^{T}A$ at all.

About 25 minutes7 activities Paper packet