The Period Function of Second Order Differential Equations

A. Raouf Chouikha

We interest in the behaviour of the period function for equations of the type $u^{\prime \prime }+g(u)=0$ and $u^{\prime \prime }+f(u)u^{\prime }+g(u)=0$ with a center at the origin 0. $g$ is a function of cla…