一类Duffing型时滞微分方程的周期解

Periodic Solution for a Class of Duffing Equations with Delay

用重合度理论研究Duffing型时滞微分方程x″(t) +f(x(t) )x′(t) +g(x(t -τ(t) ) )=p(t)的

The theory of coincidence degree is used to study the existence of the 2π periodic solution of the Duffing equation with delay:x″(t)+f(x(t))x′(t)+g(x(t-τ(t)))=p(t).