Question

The Root Locus technique may be defined as
point
a method of plotting the locus of the roots of the characteristic equation of the open-
loop system in the s-plane as the gain is varied from zero to infinity
a method of plotting the locus of the roots of the characteristic equation of the
closed-loop system in the s-plane as the gain is kept constant
a method of plotting the locus of the roots of the characteristic equation of the open-
loop system in the s-plane as the gain is varied arbitrarily
a method of plotting the locus of the roots of the characteristic equation of the
closed-loop system in the s-plane as the gain is varied from zero to infinity​

Answer 1

Answer:

control theory and stability theory, root locus analysis is a graphical method for examining how the roots of a system change with variation of a certain system parameter, commonly a gain within a feedback system. This is a technique used as a stability criterion in the field of classical control theory developed by Walter R. Evans which can determine stability of the system. The root locus plots the poles of the closed loop transfer function in the complex s-plane as a function of a gain parameter (see pole–zero plot).

A graphical method that uses a special protractor called a "Spirule" was once used to determine angles and draw the root loci.[1]