Sharp Cusa and Becker-Stark inequalities

被引：45

作者：

Chen, Chao-Ping ^{[1
]}

Cheung, Wing-Sum ^{[2
]}

机构：

[1] Univ Jiaozuo City, Sch Math & Informat, Henan Polytech, Jiaozuo City 454003, Henan Province, Peoples R China

[2] Univ Hong Kong, Dept Math, Hong Kong, Hong Kong, Peoples R China

来源：

JOURNAL OF INEQUALITIES AND APPLICATIONS | 2011年

关键词：

Inequalities; trigonometric functions; HUYGENS INEQUALITIES; WILKER;

D O I：

10.1186/1029-242X-2011-136

中图分类号：

O29 [应用数学];

学科分类号：

070104 ;

摘要：

We determine the best possible constants theta,boxed times,alpha and beta such that the inequalities (2 + cos x/3)(theta) < sin x/x < (2 + cos x/3)(theta) and (pi(2)/pi(2) - 4x(2))(alpha) < tanx/x < (pi(2)/pi(2) - 4x(2))(beta) are valid for 0 < x < pi/2. Our results sharpen inequalities presented by Cusa, Becker and Stark.

引用

页数：6

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