18071 Granada, Spain
Departamento de Matematica Aplicada, Facultad de Ciencias, Universidad de Granada
Stable Periodic Solutions in the Forced Pendulum Equation
2013, vol. 18, no. 6, pp. 585-599
Consider the pendulum equation with an external periodic force and an appropriate condition on the length parameter. It is proved that there exists at least one stable periodic solution for almost every external force with zero average. The stability is understood in the Lyapunov sense.