BOUNDARY VALUE PROBLEMS FOR SECOND ORDER SINGULARLY PERTURBED DIFFERENTIAL EQUATIONS

In this paper the existence and uniqueness of solutions of boundary value problems εy″=f(t,y,ε) L(y(0),y′(0),ε) =0, R(y(1), y′(1),ε)=0(which contains the Robi’s problem) is discussed by using the upper and lower solution. In addition, the asymptotic estimation of the solution is given us well.