Notebook
\newcommand{\mat}[1]{\left[\begin{array}#1\end{array}\right]} \newcommand{\vx}{{\mathbf x}} \newcommand{\hx}{\hat{\mathbf x}} \newcommand{\vbt}{{\mathbf\beta}} \newcommand{\vy}{{\mathbf y}} \newcommand{\vz}{{\mathbf z}} \newcommand{\vb}{{\mathbf b}} \newcommand{\vu}{{\mathbf u}} \newcommand{\vv}{{\mathbf v}} \newcommand{\vw}{{\mathbf w}} \newcommand{\va}{{\mathbf a}} \newcommand{\ve}{{\mathbf e}} \newcommand{\vp}{{\mathbf p}} \newcommand{\R}{{\mathbb{R}}} \newcommand{\col}{{\operatorname{Col}}} \newcommand{\nul}{{\operatorname{Nul}}} \newcommand{\rank}{{\operatorname{rank}}} \newcommand{\setb}{{\mathcal{B}}}