A feedback control system is shown in Figure 1. The controller and process transfer function are given by = Ge(s) K and G(s) = 8+40 = s(8+10) and the feedback transfer function is H(s) = 1/(s + 20). == (a) Determine the limiting value of gain K for a stable system. (b) For the gain that results in marginal stability, determine the magnitude of the imaginary roots. Controller Process E(s) R(s) G(S) G(s) Y(s) Sensor H(s) Figure 1: Nonunity feedback system.