INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS, cilt.50, sa.7, ss.2046-2056, 2011 (SCI-Expanded)
The solutions of a class of nonlinear second-order differential equations with a cubic term in the dependent variable being related to Duffing oscillators are obtained by means of the factorization technique. The Lagrangian, the Hamiltonian and the constant of motion are also found through a correspondence with an autonomous system. A physical example is worked out in this frame.