See attachment for full problem description.
A unity feedback system has a process: (see attachment)
Determine the range of K for which the system is stable by drawing a polar plot.
The radius = K/2 for K > 1 there is P = 1 and N = -1.
Z = N + P = -1 + 1 = 0 and the system is stable for K >1.
I believe the best way to show a polar plot is to use a Nyquist plot in Matlab.
This solution of 198 words explains the unity feedback system process and includes Nyquist plots in Matlab that explains a polar plot.