Obtain the unit-acceleration response curve of the unity-feedback control system whose open loop transfer function is given by

\[G(s)=\frac{8(s+1)}{s^{2}(s+3)}\]

using MATLAB. The unit-acceleration input is defined by

\[r(t)=\frac{1}{2} t^{2} \quad(t \geq 0)\]