Some Subclasses of Univalent and Bi-Univalent Functions Related to K-Fibonacci Numbers and Modified Sigmoid Function

• Published in: Majallat Baghdād lil-ʻulūm Vol. 20; no. 3
• Main Authors: Amal Madhi Rashid, Abdul Rahman S. Juma
• Format: Journal Article
• Language: Arabic; English
• Published: College of Science for Women, University of Baghdad 01-06-2023
• Subjects: Bi-univalent function, Borel distribution, Fibonacci numbers, Modified sigmoid function, Univalent function
• ISSN: 2078-8665; 2411-7986
• DOI: 10.21123/bsj.2022.6888

            This paper is interested in certain  subclasses of univalent and bi-univalent functions concerning  to shell- like curves connected with k-Fibonacci numbers involving modified Sigmoid activation function θ(t)=2/(1+e^(-t) ) ,t ≥0 in unit disk |z|<1 . For estimating of the initial coefficients |c_2 | , |c_3 |, Fekete-Szego ̈ inequality and the  second Hankel determinant have been investigated for the functions in our classes.