Q.5 (a) Using the Routh-Hurwitz criterion, determine if the following systems are stable or unstable, and how many roots lie in the left-hand plane of the s-plane diagram.
s^3 + 2s^2 + 6
(i)
1
(ii)
(10 marks)
(b) For the negative closed-loop feedback system with an open-loop gain G(s) and a feedback gain H(s=1, where
s(s+b)
determine the range of values for the gain K when (i) a < 0 and b < 0, and (ii) a > 0 and b > 0. (10 marks)