I've got a question on the Nyquist Stability criterion.

Consider a unity negative feedback system with plant L(s) and gain K in the forward loop.

A nyquist plot is to be generated for this system to meet the following criteria:

1) L(s) has one unstable right half plane pole2) The closed loop system is stable for (1/3 < K < 2) and unstable for K=1/3 and K=2.

3) Phase margin of 30 degrees4) Zero steady state error to a step reference input.

Help !