Question

Consider a characteristic equation, s^4+3s^3+5s^2+6s+k+10=0. The condition for stability is

(a) K>5

(b) -10<K

(c) K>-4

(d) -10<K<-4

The question was posed to me during an interview.

The question is from Relative Stability Analysis topic in division Stability and Algebraic Criteria of Control Systems

Answer 1

The correct answer is (d) -10<K<-4

To elaborate: Solve Roth array for the system stable, -10<K<4.