Conversion of a differential equation to a system of first-order differential equations

From Calculus

Statement

Consider a differential equation with independent variable and dependent variable given as follows:

We can convert this to a system of first-order differential equations with variables and equations as follows.

Take the variables to be where is the variable that we will eventually set as . The system has first-order differential equations of the form:

and one more first-order differential equation:

Note that, with the exception of the last differential equation, all the other equations are autonomous (no reference to the dependent variable), first-order (the highest derivative order is one) and linear.