Automatic Control Systems - Engineering

Q1:

Consider the following statements about root locus
  1. The intersection of root locus branches with the imaginary axis can be determined by the use of Routh criterion
  2. Segments of real axis having an odd number of real axis open loop poles plus zeros to their right are not parts of root locus
  3. The number of root locus branches terminating on infinity is always zero
Which of the above statements are correct?

A 1, 2 and 3

B 1 and 2 only

C 1 only

D 2 and 3 only

ANS:B - 1 and 2 only

No answer description is available.