Second Hankel determinant for a subclass of analytic bi-univalent functions defined by subordination

Authors: AHMAD MOTAMEDNEZHAD, TEODOR BULBOACA, EBRAHIM ANALOUEI ADEGANI, NESA DIBAGAR

Abstract: In this work with a different technique we obtain upper bounds of the functional $\left|a_2a_4-a_3^2\right|$ for functions belonging to a comprehensive subclass of analytic bi-univalent functions, which is defined by subordinations in the open unit disk. Moreover, our results extend and improve some of the previously known ones.

Keywords: Bi-univalent functions, Fekete-Szego determinant, second Hankel determinant, differential subordination, Carathéodory functions

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