Centred approach to the period of anharmonic oscillators

We present a simple method for obtaining a concise series expression for the period of one-dimensional classical oscillators. The series converges well for typical potentials and is of a form that is often suitable for obtaining approximate expressions for the period valid to any order in the amplitude desired. The method is most easily applied to even potentials. However, by employing the lower turning point expansion discussed in the appendices it may readily be applied even to those potentials where the lower turning point may not be solved for explicitly in terms of the upper turning point. We demonstrate the method by obtaining expressions for the periods of both the simple pendulum and tadpole orbits.