## Journal of Applied Mathematics

### On a Generalized Hyers-Ulam Stability of Trigonometric Functional Equations

#### Abstract

Let $G$ be an Abelian group, let ${\Bbb C}$ be the field of complex numbers, and let $f,g:G\to {\Bbb C}$. We consider the generalized Hyers-Ulam stability for a class of trigonometric functional inequalities, $|f(x-y)-f(x)g(y)+g(x)f(y)|\le \psi (y), |g(x-y)-g(x)g(y)-f(x)f(y)|\le \psi (y)$, where $\psi :G\to {\Bbb R}$ is an arbitrary nonnegative function.

#### Article information

Source
J. Appl. Math., Volume 2012 (2012), Article ID 610714, 14 pages.

Dates
First available in Project Euclid: 14 December 2012

https://projecteuclid.org/euclid.jam/1355495081

Digital Object Identifier
doi:10.1155/2012/610714

Mathematical Reviews number (MathSciNet)
MR2898081

Zentralblatt MATH identifier
1244.39021

#### Citation

Chung, Jaeyoung; Chang, Jeongwook. On a Generalized Hyers-Ulam Stability of Trigonometric Functional Equations. J. Appl. Math. 2012 (2012), Article ID 610714, 14 pages. doi:10.1155/2012/610714. https://projecteuclid.org/euclid.jam/1355495081