1. Consider a system with G. 4 -0.45 e (This may look familiar :), but it is 2s+20s? +10s +1 needed for parts b and c) (a) Without solving the cubic equation determine if the system is open loop stable. (b) Calculate the ultimate response yu(t) if u'(t) = 3 sin(5t). Provide a hard (=scanned) copy of the relevant Bode plot () If a PI controller with K. =-1 and T1 =20 is used, apply the Bode stability criterion to determine whether or not the closed loop system is stable. Provide a hard (=scanned) copy of the relevant Bode plot