A sharp bound for a sine polynomial

Horst Alzer; Stamatis Koumandos

Colloquium Mathematicae (2003)

  • Volume: 96, Issue: 1, page 83-91
  • ISSN: 0010-1354

Abstract

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We prove that | k = 1 n s i n ( ( 2 k - 1 ) x ) / k | < S i ( π ) = 1 . 8519 . . . for all integers n ≥ 1 and real numbers x. The upper bound Si(π) is best possible. This result refines inequalities due to Fejér (1910) and Lenz (1951).

How to cite

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Horst Alzer, and Stamatis Koumandos. "A sharp bound for a sine polynomial." Colloquium Mathematicae 96.1 (2003): 83-91. <http://eudml.org/doc/285080>.

@article{HorstAlzer2003,
abstract = {We prove that $|∑_\{k=1\}^\{n\} sin((2k-1)x)/k| < Si(π) = 1.8519...$ for all integers n ≥ 1 and real numbers x. The upper bound Si(π) is best possible. This result refines inequalities due to Fejér (1910) and Lenz (1951).},
author = {Horst Alzer, Stamatis Koumandos},
journal = {Colloquium Mathematicae},
keywords = {sine polynomial; sine integral; inequalities},
language = {eng},
number = {1},
pages = {83-91},
title = {A sharp bound for a sine polynomial},
url = {http://eudml.org/doc/285080},
volume = {96},
year = {2003},
}

TY - JOUR
AU - Horst Alzer
AU - Stamatis Koumandos
TI - A sharp bound for a sine polynomial
JO - Colloquium Mathematicae
PY - 2003
VL - 96
IS - 1
SP - 83
EP - 91
AB - We prove that $|∑_{k=1}^{n} sin((2k-1)x)/k| < Si(π) = 1.8519...$ for all integers n ≥ 1 and real numbers x. The upper bound Si(π) is best possible. This result refines inequalities due to Fejér (1910) and Lenz (1951).
LA - eng
KW - sine polynomial; sine integral; inequalities
UR - http://eudml.org/doc/285080
ER -

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