On Direct Fuzzy Stability of General Quartic Functional Equation

Abstract

The goal of this paper is to investigate the Generalized Hyers - Ulam - Rassias (HUR) stability of general quartic functional equation (GQFE)                                                             fq(kr1 + (k -1)r2) + fq(kr1 - (k -1)r2) = 2k4fq(r1) + 2(k -1)4fq(r2)                                    +6k2(k -1)2[fq(r1 + r2) + fq(r1 - r2)] - 12k2(k - 1)2[fq(r1) + fq(r2)] in fuzzy normed spaces (F.N. spaces). The stability of the equation is proved by using direct method. The stability in sense of Hyers - Ulam and Ulam- Gavruta - Rassias is also studied.