Section 3.4

I think I need a little bit more of an understanding of how the normal equations are an unstable method when the matrix is ill conditioned and the least squares fir is a good one. I think the algorithm example helped me to understand it a little more though. I think its completely understandable about the condition number for a rectangular case but I wish that the condition number for a square matrix was introduced earlier because I don't remember seeing that equation until now in the text but I could have just missed it or forgotten.