a) For a unity feedback system having open loop transfer function given below. Make polar plot and determine stability.
G(s)H(s)= s²+2s+1/(s+0.5)(s²-0.4s+1.3)
b) How the value of damping ratio ξ effects the resonant peak of a second order system?
c) For an open loop stable system (first order), what is the condition on Nyquist plot of the system to make the closed loop system stable?