7. Determine the stability of the closed-loop transfer function using Routh's Criterion. (Consider Unity feedback)
(a) s^5 + 6s^3 + 5s^2 + 8s + 20
The auxiliary polynomial for row 4 is Q(s) = 5s^2 + 20, with Q(s) = 10, so there are two roots on the J-axis. The first column shows two sign changes, so there are two roots on the right half-plane. The balance, one root must be in the left half-plane.
10
A positive choice for e. Thus, the system is unstable, with two poles in the right half-plane.
s + 8
3 rhp, 2 lhp