Asymptotic behaviour of the solutions of second order functional differential equations

This paper presents integral criteria to determine the asymptotic behaviour of the solutions of second order nonlinear differential equations of the type y″(x)+q(x)f(y(x))=0y″(x)+q(x)f(y(x))=0, with q(x)>0q(x)>0 and f(y)f(y) odd and positive for y>0y>0, as xx tends to +∞+∞. It also compares them with the results obtained by Chanturia (1975) in [11] for the same problem.