Routh - Hurwitz Stability Criterion

Ask

First column elements of Routh's tabulation are 3,-4,-1/4,6,2. It means that there is/are

(a) two roots on the RHS of s-plane

(b) two roots on the LHS of s-plane

(c) three roots on the RHS of s-plane

(d) one root on the RHS of s-plane

 

Answer is ( a )

Concept

Explanation:Consider one pair of elements each time i.e.,Sign change (from positive to negative) 3 and -4

-4 & -1/4 : No sign change

-1/4 & 6 : Sign change (from negative to positive)

6 & 2 : No sign change:

This indicates that there are two sign changes in the first column of Routh's tabulation. Thus we have two roots on the RHS of s-plane.