The impulse response of an initially relaxed linear system is $${e^{ - 2t}}u\left( t \right).$$ To produce a response of $${te^{ - 2t}}u\left( t \right),$$ the input must be equal to

The Laplace transformation of $$f(t)$$ is $$F(s).$$ Given $$F\left( s \right) = {\omega \over {{s^2} + {\omega ^2}}},$$ the final value of $$f(t)$$ is

The steady state error due to a step input for type $$1$$ system is ______________.

The closed loop transfer function of a control system is given by $${{C\left( s \right)} \over {R\left( s \right)}}\, = \,\,{{2\left( {s - 1} \right)} \over {\left( {s + 2} \right)\left( {s + 1} \right)}}$$ for a unit step input the output is