Journal of Inequalities and Applications (Jan 2010)

Stability of Approximate Quadratic Mappings

  • Juri Lee,
  • Hark-Mahn Kim,
  • Minyoung Kim

DOI
https://doi.org/10.1155/2010/184542
Journal volume & issue
Vol. 2010

Abstract

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We investigate the general solution of the quadratic functional equation f(2x+y)+3f(2x−y)=4f(x−y)+12f(x), in the class of all functions between quasi-β-normed spaces, and then we prove the generalized Hyers-Ulam stability of the equation by using direct method and fixed point method.