Problem Of The Equvalency Of The Periodic Solutions Of Van Der Pol Equation

The ordinary differential Van der Pol equation and the functional differential Van der Pol equation with delays whose nonlinear terms are in two different forms are compared accordingly in this paper,mainly by means of the planar qualitative theory,the Hopf bifurcation theorem and the cone fixed point theorem in the functional differential equations.Their differences in the periodic solutions and hopf bifurcations are gained ,which embody the differences between the ordinary differential equations and the functional differential equations in a concrete equation to some extent.