Remarks on the method of comparison equations (generalized WKB method) and the generalized Ermakov-Pinney equation

  title={Remarks on the method of comparison equations (generalized WKB method) and the generalized Ermakov-Pinney equation},
  author={Alexander Yu. Kamenshchik and Mattia Luzzi and Giovanni Venturi},
The connection between the method of comparison equations (generalized WKB method) and the Ermakov-Pinney equation is established. A perturbative scheme of solution of the generalized Ermakov-Pinney equation is developed and is applied to the construction of perturbative series for second-order differential equations with and without turning points. 

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