Nonlinear oscillators via Čebyšëv quintic approximations

Aim of this work is the study of differential equations governing non–dissipative non–linear oscillators; these arise in different physical models such as the treatment of relativistic oscillators, up to generalizations to Duffing’s relativistic oscillators and in non–relativistic models which deals with cables with an attached midpoint mass, or some harmonic Duffing oscillators.