The loop transfer function of a feedback system is . The number of asymptotes of its root loci are

Which of the following can act as error detecting devices

1. a pair of potentiometers
2. a pair of synchros
3. a differential transformer
4. a metadyne
5. a control transformer

Select the answer using the following codes:

The M circle for M = 1 is the

For the system in the given figure G varies slightly, the ratio of open loop sensitivity to closed loop sensitivity is

For any test point s on the real axis, the sum of angular contributions of the complex conjugate poles is