Second Hankel Determinant for Certain Subclasses of Bi-starlike Functions Defined by Differential Operators

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Article Type:
Research/Original Article (دارای رتبه معتبر)
Abstract:
In this paper, we obtain  upper bounds of the initial Taylor-Maclaurin coefficients $\left\vert a_{2}\right\vert ,$ $\left\vert a_{3}\right\vert $ and $\left\vert a_{4}\right\vert $ and of the Fekete-Szegö functional $\left\vert a_{3}-\eta a_{2}^{2}\right\vert $ for certain subclasses of analytic and bi-starlike functions $\mathcal{S}_{\sigma }^{\ast }(\beta,\theta ,n,m)$ in the open unit disk. We have also obtained an upper bound of the functional $\left\vert a_{2}a_{4}-a_{3}^{2}\right\vert $ for the functions in the class $\mathcal{S}_{\sigma }^{\ast }(\beta ,\theta ,n,m)$. Moreover, several interesting applications of the results presented here are also discussed.
Language:
English
Published:
Sahand Communications in Mathematical Analysis, Volume:20 Issue: 2, Spring 2023
Pages:
65 to 83
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