Copyright © 2009 R. Saadati et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Recently, Baktash et al. (2008) proved the stability of the cubic functional
equation f(2x+y)+f(2x−y)=2f(x+y)+2f(x−y)+12f(x) and the quartic
functional equation f(2x+y)+f(2x−y)=4f(x+y)+4f(x−y)+24f(x)−6f(y) in random normed spaces. In this note, we correct the proofs.