Salas, Alvaro H. S.Cieza Altamirano, GilderSánchez-Chero, Manuel2023-03-072023-03-072022-07-11http://hdl.handle.net/20.500.14142/355In this paper, we generalize He’s frequency approach for solving the damped Duffing equation by introducing a time varying amplitude. We also solve this equation by means of the homotopy method and the Lindstedt–Poincaré method. High accurate formulas for approximating the Jacobi elliptic function cn are formally derived using Chebyshev and Pade approximation techniques.application/pdfenginfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/4.0/homotopyLindstedt–Poincaréinfo:eu-repo/semantics/articlehttps://doi.org/10.1155/2022/5009722http://purl.org/pe-repo/ocde/ford#1.06.06