Fixed Points and Generalized Hyers–ulam Stability of Quadratic Functional Equations
نویسندگان
چکیده
Let X, Y be complex vector spaces. It is shown that if a mapping f : X → Y satisfies f (x + iy) + f (x− iy) = 2f (x) − 2f (y) (0.1) or f (x + iy) − f (ix + y) = 2f (x) − 2f (y) (0.2) for all x, y ∈ X , then the mapping f : X → Y satisfies f (x + y) + f (x− y) = 2f (x) + 2f (y) for all x, y ∈ X . Furthermore, we prove the generalized Hyers-Ulam stability of the functional equations (0.1) and (0.2) in complex Banach spaces.
منابع مشابه
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