Consider a unity negative feedback control system with open-loop transfer function: (a) L(s)=G(s)G(s) = - 10 s+2s+4 10s +1 s(s+0.5)(S-1) Obtain the Nyquist plot in MATLAB and use Nyquist Criterion to check stability. If the system is unstable, how many unstable poles does the closed-loop system have? If the system is stable, what is the maximum unmodeled delay the system can tolerate before going unstable? (b) L(s)=G(s)G(s)=G(s) =