This paper studies analytic functions f defined on the open unit disk of the complex plane for which f / g and (1 + z ) g / z are both functions with positive real part for some analytic function g . We determine radius constants of these functions to belong to classes of strong starlike functions, starlike functions of order α , parabolic starlike functions, as well as to the classes of starlike functions associated with lemniscate of Bernoulli, cardioid, lune, reverse lemniscate, sine function, exponential function and a particular rational function. The results obtained are sharp.

中文翻译：

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某些解析函数的星状半径

本文研究了在复平面的开单位圆上定义的解析函数f，其中f / g和（1 + z）g / z均为带有实数的正函数的解析函数g。我们确定这些函数的半径常数属于强恒星函数，α阶恒星函数，抛物线恒星函数的类别，以及与伯努利的lemniscate，心形，lune，反向lemniscate，正弦函数相关的星形函数的类别，指数函数和特定的有理函数。获得的结果是清晰的。