Ulam stability problem for generalized A-quadratic mappings

It is the purpose of this paper to investigate the stability problem of Ulam for an approximate mapping for the following generalized quadratic functional equation: n i=1 Q j =i xj −(n −1)xi + nQ n i=1 xi = n2 n i=1 Q(xi ) for all xi (i = 1, . . . , n), where n>1.  2004 Elsevier Inc. All rights reserved