Some remarks for certain subclasses of meromorphic 1 ? valent functions

Abstract

In this paper, a boundary version of the Schwarz lemma for classes N(?) is investigated. For the function (Formula Presented) defined in the punctured unit disc D = {z ? ?: 0 < |z| < 1} such that f(z) ? N(?), we estimate a modulus of the angular derivative of f ?? (z) function at the boundary point b with (Formula presented). The sharpness of these inequalities is also proved. © 2017, Transilvania University of Brasov 1. All rights reserved.