Consider the system described by following state space equations
$\begin{vmatrix} \dot{x_1}\\ \dot{x_2} \end{vmatrix}=\begin{vmatrix} 0 &1 \\ -1 & -1 \end{vmatrix}\begin{vmatrix} x_1\\x_2 \end{vmatrix}+\begin{vmatrix} 0\\1 \end{vmatrix}u$ ; $y=\begin{vmatrix} 1 & 0 \end{vmatrix}\begin{vmatrix} x_1\\ x_2 \end{vmatrix}$
If $u$ is unit step input, then the steady state error of the system is
- $0$
- $1/2$
- $2/3$
- $1$