A unity feedback system has open-loop transfer function $$G(s) = {1 \over {s\left( {2s + 1} \right)\left( {s + 1} \right)}}$$

Sketch Nyquist plot for the system and there from obtain the gain margin and the phase margin.

The magnitude plot of the open loop transfer function G(s), of a certain system is given in fig,

(a) Determine G(s), if it is known that the system is of minimum phase type.

(b) Estimate the phase at each of the corner frequencies.