Journal of the Ramanujan Mathematical Society
Volume 36, Issue 3, September 2021 pp. 193–202.
Some refinements of well-known inequalities involving trigonometric functions
Authors:
Abd Raouf Chouikha, Christophe Chesneau and Yogesh J. Bagul
Author institution:
4, Cour des Quesblais 35430 Saint-Pere
Summary:
In this paper, we determine new and sharp inequalities involving
trigonometric functions. More specifically, a new general result
on the lower bound for log (1 - uv), u, v ∈ (0, 1) is proved,
allowing to determine sharp lower and upper bounds for the
so-called sinc function, i.e., sin (x)/x, lower bounds for
cos (x) and upper bounds for (cos (x/3)){3}. The obtained
bounds improve some well-established results. The findings are
supported by graphical analyses.
Contents
Full-Text PDF