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Radius of starlikeness of certain analytic functions

  • Asha Sebastian EMAIL logo and V. Ravichandran
Published/Copyright: January 29, 2021
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Abstract

This paper studies analytic functions f defined on the open unit disk of the complex plane for which f/g and (1 + z)g/z are both functions with positive real part for some analytic function g. We determine radius constants of these functions to belong to classes of strong starlike functions, starlike functions of order α, parabolic starlike functions, as well as to the classes of starlike functions associated with lemniscate of Bernoulli, cardioid, lune, reverse lemniscate, sine function, exponential function and a particular rational function. The results obtained are sharp.

MSC 2010: 30C80; 30C45

Dedicated to Dato’ Indera Rosihan M. Ali on the occasion of his 62nd birthday


  1. Communicated by Marek Balcerzak

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Received: 2020-01-23
Accepted: 2020-04-25
Published Online: 2021-01-29
Published in Print: 2021-02-23

© 2021 Mathematical Institute Slovak Academy of Sciences

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