Differential equation - Wikipedia
https://en.wikipedia.org/wiki/Differential_equationDifferential equations first came into existence with the invention of calculus by Newton and Leibniz. In Chapter 2 of his 1671 work Methodus fluxionum et Serierum Infinitarum, Isaac Newton listed three kinds of differential equations: In all these cases, y is an unknown function of x (or of x1 and x2), and f is a given function. He solves these examples and others using infinite series and discusses the non-uniqueness of …