Formulas for the amplitude of the van der Pol limit cycle

Jose-Luis Lopez, Saied Abbasbandy, Ricardo Lopez-Ruiz

The limit cycle of the van der Pol oscillator, $\ddot{x}+\epsilon (x^2-1)\dot{x}+x=0$, is studied in the plane $(x,\dot{x})$ by applying the homotopy analysis method. A recursive set…