Oscillation criteria are given for second order nonlinear differential equations with damping of the form (a(t) y (x ) \dot x)\dot{}+ p(t) \dot x + q (t) f (x ) = 0,\quad t\geq t0, where p and q are allowed to change signs on [t0,\infty). We employ the averaging technique to obtain sufficient conditions for oscillation of solutions of the above equation. Our results generalize and extend some known oscillation criteria in the literature.

Oscillation criteria are given for second order nonlinear differential equations with damping of the form (a(t) y (x ) \dot x)\dot{}+ p(t) \dot x + q (t) f (x ) = 0,\quad t\geq t0, where p and q are allowed to change signs on [t0,\infty). We employ the averaging technique to obtain sufficient conditions for oscillation of solutions of the above equation. Our results generalize and extend some known oscillation criteria in the literature.