Abstract
The aim of this particular article is at studying a holomorphic function f defined on the open-unit disc D = {z is an element of C : |z| < 1} for which the below subordination relation holds zf ' (z)/f(z) < q(0)(z) = 1 + tan h(z). The class of such functions is denoted by S*(tan h): The radius constants of such functions are estimated to conform to the classes of starlike and convex functions of order beta and Janowski starlike functions, as well as the classes of starlike functions associated with some familiar functions.