Fixed Point Theory and Applications 
Volume 2008 (2008), Article ID 945010, 7 pages
doi:10.1155/2008/945010
Research Article

A Fixed Point Approach to the Stability of a Functional Equation of the Spiral of Theodorus

Soon-Mo Jung1 and John Michael Rassias2

 1Mathematics Section, College of Science and Technology, Hong-Ik University, 339-701 Chochiwon, South Korea
2Mathematics Section, Pedagogical Department, National and Capodistrian University of Athens, 4 Agamemnonos Street, Aghia Paraskevi, Attikis, 15342 Athens, Greece
Received 2 April 2008; Accepted 26 June 2008

Recommended by Fabio Zanolin

Abstract

Cădariu and Radu applied the fixed point method to the investigation of Cauchy and Jensen functional equations. In this paper, we adopt the idea of Cădariu and Radu to prove the stability of a functional equation of the spiral of Theodorus, f(x+1)=(1+i/x+1)f(x).