Positive solutions of third order damped nonlinear differential equations

summary:We study solutions tending to nonzero constants for the third order differential equation with the damping term \[ (a_{1}(t)(a_{2}(t)x'(t))')'+q(t)x'(t)+r(t)f(x(\varphi (t)))=0 \] in the case when the corresponding second order differential equation is oscillatory