Stability Pexided functional equation

Stability Pexided functional equation

In the paper we establish the Hyers-Ulam stability of the following functional equation f(2x + y) + f(2x - y) = 2g(x + y) + 2g(x - y) + 2g(2x) - 4g(x) in topological vector spaces, where f, g are functions dened on a group with values in a topological vector spaces.