FEKETE-SZEGO problem for a class of analytic functinos defined by convolution

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Published: Jun 29, 2013
DOI: https://doi.org/10.5556/j.tkjm.44.2013.1162
Keywords:
Analytic functions Starlike functions Convex functions Subordination

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Sivaprasad Kumar Shanmugam
Department of AppliedMathematics, Delhi Technological University, Delhi-110042, India.
Virendra Kumar
Department of AppliedMathematics, Delhi Technological University, Delhi-110042, India.

Abstract

Let $g$ and $h$ be two fixed normalized analytic functions and $\phi$ be starlike with respect to $1,$ whose range is symmetric with respect to the real axis. Let $\mathcal{M}^{\alpha,\beta}_{g,h}(\phi)$ be the class of analytic functions $f(z)=z+a_2z^2+a_3z^3+\ldots$, satisfying the subordination $$\left(\frac{(f*g)(z)}{z}\right)^\alpha \left(\frac{(f*h)(z)}{z}\right)^{\beta}\prec \phi(z),$$ where $\alpha$ and $\beta$ are real numbers and are not zero simultaneously. In the present investigation, sharp upper bounds of the Fekete-Szego functional $|a_3-\mu a_2^2|$ for functions belonging to the class $\mathcal{M}^{\alpha,\beta}_{g,h}(\phi)$ are obtained and certain applications are also discussed.

Article Details

How to Cite
Shanmugam, S. K., & Kumar, V. (2013). FEKETE-SZEGO problem for a class of analytic functinos defined by convolution. Tamkang Journal of Mathematics, 44(2), 187–195. https://doi.org/10.5556/j.tkjm.44.2013.1162
Issue
Vol. 44 No. 2 (2013)
Section
Papers

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