Oscillation theorems for second order nonlinear differential equations with damping

Some oscillation criteria for solutions of a general ordinary differential equation of second order of the form (r(t)?(x(t))?(t))ʹ +h(t)?(t)+q(t)? (g(x(t)); r(t)?(x(t))?(t)) = H(t,x(t),?(t)) with alternating coefficients are discussed. Our results improve and extend some existing results in the literature. Some illustrative examples are given with its numerical solutions which are computed using Runge Kutta method of fourth order.