On linearizability via nonlocal transformations and first integrals for second-order ordinary differential equations

TL;DR

This paper introduces a new family of integrable second-order nonlinear differential equations through nonlocal transformations, providing their first integrals and solutions, and applying these results to classical oscillators like Duffing and Van der Pol.

Contribution

It presents a novel classification of second-order ODEs that admit transcendental first integrals via nonlocal transformations, expanding the understanding of their integrability.

Findings

Derived a new family of integrable second-order ODEs.

Constructed explicit first integrals for these equations.

Applied results to find periodic solutions and limit cycles.

Abstract

Nonlinear second-order ordinary differential equations are common in various fields of science, such as physics, mechanics and biology. Here we provide a new family of integrable second-order ordinary differential equations by considering the general case of a linearization problem via certain nonlocal transformations. In addition, we show that each equation from the linearizable family admits a transcendental first integral and study particular cases when this first integral is autonomous or rational. Thus, as a byproduct of solving this linearization problem we obtain a classification of second-order differential equations admitting a certain transcendental first integral. To demonstrate effectiveness of our approach, we consider several examples of autonomous and non-autonomous second order differential equations, including generalizations of the Duffing and Van der Pol oscillators, and construct their first integrals and general solutions. We also show that the corresponding first integrals can be used for finding periodic solutions, including limit cycles, of the considered equations.