Solutions of a quadratic nonlinear oscillator: Iteration procedure

A modified iteration procedure is applied to a quadratic nonlinear oscillator (QNO). When the solutions of the two auxiliary equations are available, we obtain the first and second analytical approximate solutions to the QNO. Our second approximation result significantly improves on the accuracy of the approximate solution obtained by using the first-order harmonic balance method. (c) 2006 Elsevier Ltd. All rights reserved.