On a class of analytic functions. I (Q581582)

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scientific article; zbMATH DE number 4019393
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On a class of analytic functions. I
scientific article; zbMATH DE number 4019393

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    On a class of analytic functions. I (English)
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    1987
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    The authoress mainly defines the new class R(\(\alpha)\) consisting of holomorphic functions \(f(z)=z+a_ 2z^ 2+..\). in the open unit disc E in \({\mathbb{C}}\) with f(z)\(\neq 0\) in E-\(\{\) \(0\}\) and f'(0)\(\neq 0\) in E satisfying \[ Re\{z^{\alpha -1}f'{}^{\alpha}(z)f^{1- \alpha}(z)/(g(z)h(z))\}>0\quad in\quad E, \] \(g\in S^*\), \(h\in K\). She finds the radius of \(\alpha\)-convexity for this class and establishes estimates for \(| a_ 2|\) and \(| a_ 3|\). A representation formula for \(f\in R(\alpha)\) is also derived. Similar results are given for two more new classes. These results are generalations of earlier results by \textit{R. Bharati} [Indian J. Pure Appl. Math. 9, 1118-1130 (1978; Zbl 0394.30006); Proc. Indian Acad. Sci., Sect. A, Part III 88, 93-103 (1979; Zbl 0416.30012)].
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    radius of \(\alpha \)-convexity
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