Plot the specified output by using the RK4 method.

\(\left\{\begin{array}{ll}\dot{x}_{1}=-2 x_{1}-x_{2}^{3}+e^{-t} \cos t, & x_{1}(0)=0 \\ \dot{x}_{2}=x_{1}+4 & x_{2}(0)=\frac{2}{3}\end{array}, 0 \leq t \leq 5\right.\), outputs : \(x_{1}, x_{2}\)