In the derivation of expression for peak percent overshoot,
$M_{p}=\exp \left(\frac{-\pi \zeta}{\sqrt{1-\zeta^{2}}}\right) \times 100 \%$, which one of the following conditions is NOT required?
- System is linear and time invariant.
- The system transfer function has a pair of complex conjugate poles and no zeroes.
- There is no transportation delay in the system.
- The system has zero initial conditions.