DIFFERENTIAL SUBORDINATIONS USING RUSCHEWEYH DERIVATIVE AND SALAGEAN OPERATOR

Abstract

In the present paper we study the operator defined by using the Ruscheweyh derivative R mf z and the S˘al˘agean operator S mf z , denoted L m α : An → An, Lm α f z = 1−α R mf z +αSmf z , z ∈ U, where An = {f ∈ H U : f z = z+an+1z n+1+. . . , z ∈ U} is the class of normalized analytic functions. We obtain several differential subordinations regarding the operator L m α