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  • Research Article
  • Open Access

On the Superstability Related with the Trigonometric Functional Equation

Advances in Difference Equations20092009:503724

  • Received: 22 August 2009
  • Accepted: 6 November 2009
  • Published:


We will investigate the superstability of the (hyperbolic) trigonometric functional equation from the following functional equations: , , , , which can be considered the mixed functional equations of the sine function and cosine function, of the hyperbolic sine function and hyperbolic cosine function, and of the exponential functions, respectively.


  • Differential Equation
  • Partial Differential Equation
  • Ordinary Differential Equation
  • Functional Analysis
  • Functional Equation

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Authors’ Affiliations

Department of Mathematics, Kangnam University, Youngin, Gyeonggi, 446-702, South Korea