Periodic solutions of nonautonomous second order differential equations with a singularity

Abstract

In this paper we consider general nonautonomous second order ordinary differential equations with singular nonlinearities. We previde sufficient conditions on the nonlinearity to prove the existence of at least one solution. We combine the topological degree with the method of upper and lower solutions.

Keywords:

• Periodic solutions
• nonautonomous differential equations
• singularity
• topological degree
• upper and lower solutions

AMS:

• 34C25