Compute the error r(xo) (also called the residual) at xo for the matrix a and the inhomogeneous term b given below. use the normal equation to find the least squares solution to ax = b. compute the minimum residual obtained by least squares approximation, and compare its norm to the norm of r(xo). 2 a=[1 3-1 -2 2 2] b= [1 0 0 ] x0 = [1 1]