Hyers-Ulam stability of an alternative functional
equation of Jensen type
Choodech Srisawat
ABSTRACT: Given an integer λ∉ {-2,-1,0, 2}, we investigate the Hyers-Ulam stability of an alternative Jensen's
functional equation ƒ (x y-1) - 2ƒ (x) + ƒ (x y) = 0 or f (x y-1) - λƒ (x) + ƒ (x y) = 0 where f is a mapping from an
abelian group to a Banach space.