“…In 1992, S. Czerwik [13], in the spirit of Hyers-Ulam-Rassias generalized the Skof's theorem. Recently, the stability problem of the K-quadratic functional equation has been investigated by a number of mathematicians, the interested reader should refer to Ait Sibaha , Bouikhalene and Elqorachi [1], B.Bouikhalene, et al [5], A.Charifi, et al [10], Ab.Chahbi, et al [9] and R. Lukasik [27], see also [6], [20], [22]- [25] and [32]. In 1998 Jung [22] investigated the Hyers-Ulam stability for additive and quadratic mappings on restricted domains.…”