Chapter 5.4, Problem 12E

Using Exercise 10 as a guide, define theterm minimal least-squares solution of a linear system. Explain whythe minimal least-squares solution $\stackrel{\to }{x}*$ of a linear system $A\stackrel{\to }{x}=\stackrel{\to }{b}$ is in ${\left(\ker A\right)}^{\perp }$ .