discussion of this issue. Definitions Ordinary differential equation Let y be an unknown function y: \mathbb{R} \to \mathbb{R} in x with y^{(n)} the n th derivative of y , and let F be a given function F:\mathbb{R}^{n+1}\rightarrow\mathbb{R}, then an equation of the form F(x,y,y',\ \dots,\ y^{(n-1)})=y^{(n)} is called an ordinary differential