Pólya’s Looking Back: an Example with Leibniz’s Integrating Factor and Linear Difference Equations

Resumo

Polya’s four phases have been well-known worldwide and have improved our problem solving skills through the years. However, it has been hard for us to find good examples of solutions obtained by using Polya’s recommendations that could be useful in our courses, we start to develop some by ourselves. In special, the looking back seems to be most neglected one among all four phases. This article shows how looking back, a la Pólya, at the classical Leibniz’s integrating factor lead us to an integrating factor method for first order linear difference equations.