Sharp inverse logarithmic coefficient bounds for starlike functions associated with cosine function

Isha Zahid; Umar Raza; Mohsan Raza

doi:10.24193/subbmath.2026.1.06

Authors

Isha Zahid Department of Mathematics, University of Jhang, Pakistan https://orcid.org/0009-0009-5763-7401
Umar Raza Department of Mathematics, University of Jhang, Pakistan https://orcid.org/0000-0001-7030-4964
Mohsan Raza Department of Mathematics, Government College University Faisalabad, Pakistan https://orcid.org/0000-0001-7466-7930

DOI:

https://doi.org/10.24193/subbmath.2026.1.06

Keywords:

Starlike functions, inverse logarthmic coefficients, Hankel determinant, Toeplitz determinant

Abstract

Let \(\mathcal{S}_{cos}^{\ast }\) be the subclass of starlike functions \(f\) associated with cosine function defined by \(\left( zf^{\prime
}(z)/f(z)\right) \prec \cos (z)\). In this paper, we obtain the sharp coefficient bounds and Hankel determinants of second order for the inverse logarithmic function for this class. We also present the best possible bounds of second order Toeplitz determinant for the functions in the same class.

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