Second-order differential equation

Definition

The term second-order differential equation is used for any differential equation whose order is 2. In other words, it is a differential equation of the form:

$F\left(x,y,y',y''\right)=0$

where $F$ is an expression (function) involving the four variables. Note that $F$ must make use of $y''$ though its use of the other variables is optional.

For more on general theory and terminology, see differential equation.