On the number of periodic solutions of a generalized pendulum equation

Zbynek Kubacek, Boris Rudolf

Katedra matematickej analyzy a numerickej matematiky, Fakulta matematiky, fyziky a informatiky UK, Mlynska dolina, 842, 48 Bratislava, Slovak Republic

E-mail. kubacek@fmph.uniba.sk

For a generalized pendulum equation we estimate the number of periodic solutions from below using lower and upper solutions and from above using a complex equation and Jensen's inequality.

AMSclassification. 34B15, 34C25.

Keywords. Generalized pendulum, number of solutions, Jensen's inequality.