Communications of the
Korean Mathematical Society
CKMS

ISSN(Print) 1225-1763 ISSN(Online) 2234-3024

Article

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Commun. Korean Math. Soc. 2010; 25(3): 373-383

Printed September 1, 2010

https://doi.org/10.4134/CKMS.2010.25.3.373

Copyright © The Korean Mathematical Society.

The geometric convexity of a function involving gamma function with applications

Yuming Chu, Xiaoming Zhang, and Zhihua Zhang

Huzhou teachers college, Haining radio and tv University, Zixing municipal school

Abstract

In this paper, we prove that $\left(\Gamma(x)\right)^{\frac{1}{x-1}}$ is geometrically convex on $(0,\infty).$ As its applications, we obtain some new estimates for $\frac{[\Gamma(x+1)]^{\frac{1}{x}}}{[\Gamma(y+1)]^{\frac{1}{y}}}$.

Keywords: gamma function, geometrically convex function, geometrically concave function, monotonicity

MSC numbers: 26D15