Determination of periodic solution for a u1/3 force by Heʹs modified Lindstedt–Poincaré method

This paper applies Heʹs modified Lindstedt–Poincaré method to determine the periodic solutions of oscillators in a u1/3 force. The result obtained and comparison with analytical solution provides confirmation for the validity of Heʹs Modified Lindstedt–Poincaré method.