Existence of Solutions for the Boundary Value Problem

The existing of solutions for the following boundary value problem of fractional differential equations is studied.{cDαu(t) +λcDα-1u(t) +f(t,u(t) ) =0,0t1,u(0) =0,u(1) =0,where 1α≤2,0≤λ18,cDα is Caputo fractional derivative,and f∶[0,1]×R→R is continuous.Under several types of sufficient conditions,the existence of solutions to the above problem is proved by a fixed-point theorems.