3. We have a system with the following difference equation: y [n] = T x [n] = 2p cos wo) y [n 1] py [n 2] + x [n] 2 cos ) x [n 1] + x[n 2]. (a) For p = 0.9 and wo = 5, find the expression for the frequency response of the system. (b) Plot the frequency response you obtained in part (a) for -A5W