The unit impulse response of a second order under-damped system starting from rest is given by $$c\left( t \right) = 12.5{e^{ - 6t}}\,\sin 8t,\,\,t \ge 0.$$
The steady-state value of the unit step response of the system is equal to

The block diagram shown in fig given is a unity feedback closed loop control system. The steady state error in the response of the above system to unit step input is

A control system with certain excitation is governed by the following mathematical equation $$${{{d^2}x} \over {d{t^2}}} + {1 \over 2}{{dx} \over {dt}} + {1 \over {18}}x = 10 + 5{e^{ - 4t}} + 2{e^{ - 5t}}$$$
The natural time constants of the response of the system are

The roots of the closed loop characteristic equation of the system shown in fig is