(b) Find a suitable contour Ts in the .v-plane that can be used to determine whether all the roots of the characteristic equation have real parts less than s = -σ1.
(c) Using the contour of part (b) and Cauchy's theorem, determine whether the following characteristic equation has roots with real parts less than s = -1:
q{s) = s3 + lis2 + 56s + 96.