Introduction
A non-linear system, in contrast to a linear system, is a system which does not satisfy the superposition principle – meaning that the output of a nonlinear system is not directly proportional to the input.
Typically, the behavior of a non-linear system is described by a nonlinear system of equations. Non-linear problems are of interest of many fields : engineers, physicists and mathematicians and many other scientists because most systems are inherently nonlinear in nature.
As a simple equation that describes a non-linear systems, we can cite the first order non-linear differential equation:
