An upper bound for the distance between a zero and a critical point of a solution of a second order linear differential equation

This paper presents an upper bound for the distance between a zero and a critical point of a solution of the second order linear differential equation (p(x)y′)′+q(x)y(x)=0(p(x)y′)′+q(x)y(x)=0, with p(x),q(x)>0p(x),q(x)>0. It also compares it with previous results.