Exercise 3. (0.3 Points) Let mn, let A=[In0]Rmn be the mn identity matrix (the principal submatrix of the mm identity matrix Im ), where 0 denotes the (mn)n zero matrix (matrix with only zero entries) and let b=[b1,,bm]Rm be a vector. Find the least squares solution of Ax=b and the 2-norm error, i.e., Axb2