Fig. P4.9 shows a network with three inputs and three outputs. (a) Derive a set of equations characterizing the network. (b) Express the equations obtained in part (a ) in the form y = Mx where y and x are column vectors given by [ y1 (nT ) y2 (nT ) y3 (nT )]T and [x1 (nT ) x2 (nT ) x3 (nT )]T , respectively, and M is a 3 3 matrix.