0.5 -0.5 0.5 -0.5 Let A = Note that the columns of A are orthonormal (why?). 0.5 0.5 0.5 0.5 (a) Solve the least squares problem Ax = b where b = * = (b) Find the projection matrix P that projects vectors in R* onto R(A) P = (c) Compute Ax and Pb Ax = Pb =