Estimation of derivatives for regular positive real part functions

Authors

  • Wenfa Yuan
  • Dongli Chen
  • Huiguang Kang

DOI:

https://doi.org/10.5556/j.tkjm.36.2005.111

Abstract

In this paper, we mainly discuss the problem of estimating the $n$th derivative of regular positive real part functions: $ g(z)=c_0+c_1z+\cdots+c_nz^n+\cdots $, which is regular in $ |z|<1 $ and $ \Re g(z)>0 $. With the principle of inductive method and the characters of regular positive real part functions, the estimation of the $n$th derivative for the function $ g(z) $ is presented. The derivative estimation for positive functions with real part has been solved completely.

Author Biographies

Wenfa Yuan

College of Science, Xi’an University of Architecture & Technology, Xi’an, Shaanxi 710055, P. R. China.

Dongli Chen

College of Science, Xi’an University of Architecture & Technology, Xi’an, Shaanxi 710055, P. R. China.

Huiguang Kang

Department of Mathematics, An’yang Teacher College, An’yang He’nan, 455000, P. R. China.

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Published

2005-09-30

How to Cite

Yuan, W., Chen, D., & Kang, H. (2005). Estimation of derivatives for regular positive real part functions. Tamkang Journal of Mathematics, 36(3), 193-197. https://doi.org/10.5556/j.tkjm.36.2005.111

Issue

Section

Papers