Periodic Solutions For Some Kinds Of Functional Differential Equations

This dissertation is mainly concerned with the existence of periodic solutions for some kinds of functional differential equations.In the first chapter , we study one kind of second order functional differential equation with multiple deviating arguments by means of continuation theorem of coincidence degreeFurthermore , we establish some relations between the existence of periodic solution and the multiple deviating arguments Tj(t).In the second chapter , we study another kind of second order differential equation with complicated deviating argumentsIn fact , Lin Zhuangpeng has studied this equation . But, we obtain some new results , that is the essential improvement of the theorem in the original paper.In the third chapter , through discussing the following variable coefficient equationswe give an estimation for the bound of its 2π—periodic solution . Then we use Shauder's fixed point theorem to study the periodic solutin of the following nonlinear equationsSome new results are obtained.