The Generalized Hyers--Ulam--Rassias Stability of a Cubic Functional Equation

In this paper, we obtain the general solution and the generalized Hyers--Ulam--Rassias stability for a cubic functional equation f(mx+y)+f(mx-y)=mf(x+y)+mf(x-y)+2(m3-m)f(x) for a positive integer m \geq 1.

The Generalized Hyers--Ulam--Rassias Stability of a Cubic Functional Equation

In this paper, we obtain the general solution and the generalized Hyers--Ulam--Rassias stability for a cubic functional equation f(mx+y)+f(mx-y)=mf(x+y)+mf(x-y)+2(m3-m)f(x) for a positive integer m \geq 1.

___

  • Acz´el, J., Dhombres, J.: Functional Equations in Several Variables. Cambridge University Press, 1989.
  • Baker, J.: The stability of the cosine equation. Proc. Amer. Math. Soc. 80, 411–416 (1980).
  • Cholewa, P. W.: Remarks on the stability of functional equations. Aequationes Math. 27, –86 (1984).
  • Czerwik, S.: On the stability of the quadratic mapping in normed spaces. Abh. Math. Sem. Univ. Hamburg 62, 59–64 (1992).
  • Forti, G. L.: Comments on the core of the direct method for proving Hyers–Ulam stability of functional equations. J. Math. Anal. Appl. 295, 127–133 (2004).
  • Grabiec, A.: The generalized Hyers–Ulam stability of a class of functional equations. Publ. Math. Debrecen. 48, 217–235 (1996).
  • Hyers, D. H.: On the stability of the linear functional equation. Proc. Natl. Acad. Sci. U.S.A. , 222–224 (1941).
  • Hyers, D. H., Isac, G., and Rassias, Th. M.: Stability of Functional Equations in Several Variables. Birkh¨auser, Basel, 1998.
  • Hyers, D. H., Isac, G., and Rassias, Th. M.: On the asymptoticity aspect of Hyers–Ulam stability of mappings. Proc. Amer. Math. Soc. 126, 425–430 (1998).
  • Hyers, D. H., Rassias, Th. M.: Approximate homomorphisms. Aequationes Math. 44, 125– (1992).
  • Jun, K. W., Kim, H. M.: The generalized Hyers–Ulam–Rassias stability of a cubic functional equation. J. Math. Anal. Appl. 274, 867–878 (2002).
  • Jun , K. W., Lee, Y. H.: On the Hyers–Ulam–Rassias stability of a pexiderized quadratic inequality. Math. In eq. Appl. 4, 93–118 (2001).
  • Jung, S. M.: On the Hyers–Ulam–Rassias stability of a quadratic functional equation. J. Math. Anal. Appl. 232, 384–393 (1999).
  • Kannappan, Pl.: Quadratic functional equation and inner product spaces. Results Math. , 368–372 (1995).
  • Rassias, Th. M.: On the stability of the linear mapping in Banach spaces. Proc. Amer. Math. Soc. 72, 297–300 (1978).
  • Rassias, Th. M.: On the stability of functional equations in Banach spaces. J. Math. Anal. Appl. 251, 264–284 (2000).
  • Skof, F.: Propriet`a`a locali e approssimazione di operatori. Rend. Sem. Mat. Fis. Milano. , 113–129 (1983).
  • Ulam, S. M.: Problems in Modern Mathematics. Chap. VI, Science Ed., Wiley, New York, Abbas NAJATI Faculty of Sciences, Department of Mathematics, Mohaghegh Ardebili University Ardebil, Islamic Republic of IRAN e-mail: a.nejati@yahoo.com