4. The characteristic polynomial of a system is given by: D(s)=s6+3s5+12s4+30s3+29s2+27s+18 Determine if this system is stable, unstable or marginally stable by using Routh-Hurwitz criterion. If there are any poles of the system which are symmetrical with respect to the origin, find them. 5. Plot the step response for Problem 6 using MATLAB. From your plots, find the time constant, rise time, and settling time for given system below. Use M=3 and M=4