การศึกษาขอบเขตพหุนามตรีโกณมิติของฟังก์ชัน sinc

Abstract

The sinc function is applied in many branches of applied science, such as difference equations, approximation theory etc. Many important quantities involving the sinc function have no closed form and require a numerical evaluation. Hence, tractable and sharp bounds of them can be useful to determine their possible values and can help to understand the features of the related phenomena. For these reasons, many researchers study the bounds of the sinc function and continually refine them. This independent study has three objectives: the first is to study the trigonometric-polynomial bound of the sinc function; the second is to compare the trigonometric-polynomial bound of the sinc function that has been studied; and the third is to apply the knowledge of the polynomial-trigonometric bound of the sinc function to obtain new theorems.