Orthogonal stability of a cubic-quartic functional equation

Volume 5, Issue 1, pp 28--36 http://dx.doi.org/10.22436/jnsa.005.01.04

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Authors

Choonkil Park - Department of Mathematics, Hanyang University, Seoul 133-791, Korea.

Abstract

Using fixed point method, we prove the Hyers-Ulam stability of the orthogonally cubic-quartic functional equation \[f(2x + y) + f(2x - y) = 3f(x + y) + f(-x - y) + 3f(x - y) + f(y - x) + 18f(x) + 6f(-x) - 3f(y) - 3f(-y)\quad (1)\] for all \(x, y\) with \(x \perp y\).

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Keywords

• Hyers-Ulam stability
• orthogonally cubic-quartic functional equation
• fixed point
• orthogonality space.

MSC

•  39B55
•  47H10
•  39B52
•  46H25

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