Consider a feedback system in which a phase-lead compensator

is placed in series with the plant Ge(s) = 1 +0.4s 1 + 0.04s 500 G(s) = (s+1)(s+5)(s + 10)* The feedback system is a negative unity feedback control system shown in Figure 10.38. Compute the gain and phase margin. a. G.M. dB, P.M. = 60 == b. G.M. 20.5 dB, P.M. = 47.8 = c. G.M. == 8.6 dB, P.M. = 33.6 d. Closed-loop system is unstable.