Radius Problems for Starlike Functions Associated with the Tan Hyperbolic Function

Abstract

The aim of this particular article is at studying a holomorphic function f defined on the open-unit disc D=z∈ℂ:z<1 for which the below subordination relation holds zf′z/fz≺q0z=1+tanhz. The class of such functions is denoted by Stanh∗. The radius constants of such functions are estimated to conform to the classes of starlike and convex functions of order β and Janowski starlike functions, as well as the classes of starlike functions associated with some familiar functions.