The Optimal Upper and Lower Power Mean Bounds for a Convex Combination of the Arithmetic and Logarithmic Means

For p∈ℝ, the power mean Mp(a,b) of order p, logarithmic mean L(a,b), and arithmetic mean A(a,b) of two positive real values a and b are defined by Mp(a,b)=((ap+bp)/2)1/p, for p≠0 and Mp(a,b)=ab, for p=0, L(a,b)=(b-a)/(log⁡b-log⁡a), for a≠b and L(a,b)=a, for a=b and A(a,b)=(a+b)/2, respectively. In t...

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Main Authors: Wei-Feng Xia, Yu-Ming Chu, Gen-Di Wang
Format: Article
Language:English
Published: Hindawi Limited 2010-01-01
Series:Abstract and Applied Analysis
Online Access:http://dx.doi.org/10.1155/2010/604804
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spelling doaj-3812b5f08ee54703a2523d23dd7ecde72020-11-24T22:37:40ZengHindawi LimitedAbstract and Applied Analysis1085-33751687-04092010-01-01201010.1155/2010/604804604804The Optimal Upper and Lower Power Mean Bounds for a Convex Combination of the Arithmetic and Logarithmic MeansWei-Feng Xia0Yu-Ming Chu1Gen-Di Wang2School of Teacher Education, Huzhou Teachers College, Huzhou, Zhejiang 313000, ChinaDepartment of Mathematics, Huzhou Teachers College, Huzhou, Zhejiang 313000, ChinaDepartment of Mathematics, Huzhou Teachers College, Huzhou, Zhejiang 313000, ChinaFor p∈ℝ, the power mean Mp(a,b) of order p, logarithmic mean L(a,b), and arithmetic mean A(a,b) of two positive real values a and b are defined by Mp(a,b)=((ap+bp)/2)1/p, for p≠0 and Mp(a,b)=ab, for p=0, L(a,b)=(b-a)/(log⁡b-log⁡a), for a≠b and L(a,b)=a, for a=b and A(a,b)=(a+b)/2, respectively. In this paper, we answer the question: for α∈(0,1), what are the greatest value p and the least value q, such that the double inequality Mp(a,b)≤αA(a,b)+(1-α)L(a,b)≤Mq(a,b) holds for all a,b>0?http://dx.doi.org/10.1155/2010/604804
collection DOAJ
language English
format Article
sources DOAJ
author Wei-Feng Xia
Yu-Ming Chu
Gen-Di Wang
spellingShingle Wei-Feng Xia
Yu-Ming Chu
Gen-Di Wang
The Optimal Upper and Lower Power Mean Bounds for a Convex Combination of the Arithmetic and Logarithmic Means
Abstract and Applied Analysis
author_facet Wei-Feng Xia
Yu-Ming Chu
Gen-Di Wang
author_sort Wei-Feng Xia
title The Optimal Upper and Lower Power Mean Bounds for a Convex Combination of the Arithmetic and Logarithmic Means
title_short The Optimal Upper and Lower Power Mean Bounds for a Convex Combination of the Arithmetic and Logarithmic Means
title_full The Optimal Upper and Lower Power Mean Bounds for a Convex Combination of the Arithmetic and Logarithmic Means
title_fullStr The Optimal Upper and Lower Power Mean Bounds for a Convex Combination of the Arithmetic and Logarithmic Means
title_full_unstemmed The Optimal Upper and Lower Power Mean Bounds for a Convex Combination of the Arithmetic and Logarithmic Means
title_sort optimal upper and lower power mean bounds for a convex combination of the arithmetic and logarithmic means
publisher Hindawi Limited
series Abstract and Applied Analysis
issn 1085-3375
1687-0409
publishDate 2010-01-01
description For p∈ℝ, the power mean Mp(a,b) of order p, logarithmic mean L(a,b), and arithmetic mean A(a,b) of two positive real values a and b are defined by Mp(a,b)=((ap+bp)/2)1/p, for p≠0 and Mp(a,b)=ab, for p=0, L(a,b)=(b-a)/(log⁡b-log⁡a), for a≠b and L(a,b)=a, for a=b and A(a,b)=(a+b)/2, respectively. In this paper, we answer the question: for α∈(0,1), what are the greatest value p and the least value q, such that the double inequality Mp(a,b)≤αA(a,b)+(1-α)L(a,b)≤Mq(a,b) holds for all a,b>0?
url http://dx.doi.org/10.1155/2010/604804
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