\left\{\begin{matrix}
y'={y}_{1}\\ 
{y}_{1}'={y}_{2}\\ 
{y}_{2}'={y}_{3}\\ 
...........\\ 

{y}_{n-1}'=f\left(x,y,{y}_{1},{y}_{2},...,{y}_{n-1} \right)\end{matrix}\right.