Question

The close loop transfer function of a system is,$T\left(s\right)=\frac{s^3+4s^2+8s+16}{s^5+3s^4+5s^2+4s+3}$
The number of poles in the right half plane and in left half plane are

• A. 3, 2
• B. 1, 4
• C. 2, 3
• D. 4, 1

Answer 1

The correct option is C 2, 3

Characteristic equation is $s^5+3s^4+5s^2+4s+3=0$

The Routh table for the characteristic equation corresponding to the given transfer function is:

There are two sign changes in the first column of Routh table. So there are 2 poles in RHP. Order of the characteristic equation is 5 = number of poles

$\therefore$ No.of poles in LHP = 5 - 2 = 3