Coefficient estimates for starlike and convex functions related to sigmoid functions

M.  Raza; D. K.  Thomas; A.  Riaz

doi:10.37863/umzh.v75i5.7093

M. Raza Department of Mathematics, Government College University Faisalabad, Pakistan
D. K. Thomas Swansea University, Bay Campus, Swansea, United Kingdom
A. Riaz Department of Mathematics, COMSATS University Islamabad, Lahore Campus, Pakistan

DOI: https://doi.org/10.37863/umzh.v75i5.7093

Keywords: Analytic functions, starlike, convex, sigmoid function, coefficient bounds, Zalcman functional

Abstract

UDC 517.5

We give sharp coefficient bounds for starlike and convex functions related to modified sigmoid functions. We also provide some sharp coefficients bounds for the inverse functions and sharp bounds for the initial logarithmic coefficients and some coefficient differences.

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