... functional equation is near to a true solution of that functional equation, and issuper superstable if every approximately solution is an exact solution of it see 14. Recently, the first and ... Modern Mathematics, chapter VI, John Wiley & Sons, New York, NY, USA,Science edition, 1940.2 D. H. Hyers, On the stability of the linear functional equation,” Proceedings of the National ... and Applications The work has been extended to quadratic functional equations. Consider f : X→Yto bea mapping such that ftx is continuous in t ∈ R, for all x ∈X. Assume that there existconstants...