## Abstract

This study deals with analytic functions with bounded turnings, defined in the disk

Od = {z : |z| < 1}. These functions are subordinated by sigmoid function 2

1+e−z and their class is

denoted by BTSg. Sharp coefficient inequalities, including the third Hankel determinant for class

BTSg, were investigated here. The same was also included for the logarithmic coefficients related to

functions of the class BTSg.

Od = {z : |z| < 1}. These functions are subordinated by sigmoid function 2

1+e−z and their class is

denoted by BTSg. Sharp coefficient inequalities, including the third Hankel determinant for class

BTSg, were investigated here. The same was also included for the logarithmic coefficients related to

functions of the class BTSg.

Original language | English |
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Article number | 3862 |

Number of pages | 24 |

Journal | Mathematics |

Volume | 2022 |

Issue number | 10 |

Publication status | Published - 18 Oct 2022 |

## Keywords

- bounded turning function
- logarithmic coefficients
- Hankel determinant
- sigmoid function