POSITIVE PERIODIC SOLUTIONS OF NONLINEAR DIFFERENTIAL EQUATIONS

查看全文 作　　者：[1]LiuYuji;[2]GeWeigao 机构地区：[1]Dept.ofMath.,YueyangTeacher‘sUniv.,Yueyang414000,China;[2]Dept.ofAppl.Math.,BeijingInstituteofTechnology,Beijing100081,China 出　　处：《Applied Mathematics(A Journal of Chinese Universities)》索引2003年第18卷第4期,共10页 基　　金：The first author was supported by the Science Foundation of Educational Committee of HunanProvince ( 99C0 1 ) and the second author by the National Natural Science Foundation of China ( 1 9871 0 0 5 ) 摘　　要：The nonlinear differential equationx′(t)=-δ(t)x(t)+f(t,x(t))(*)is considered,where δ(t) is a periodic function of periodic T,f(t,x) is continuous and periodic in t.It is showed that (*) has at least two positive T-periodic solutions under certain growth conditions imposed on f.Applications will be presented to illustrate the main results. 关 键 词：正周期解 非线性微分方程 周期函数 唯一性 存在性