In this paper, we investigate the Hyers-Ulam stability problem of the following functional equation
$ f(x+y)+g(x-y) = h(x)+k(y), $
on an unbounded restricted domain, which generalizes some of the results already obtained by other authors (for example [
Citation: Mohammad Amin Tareeghee, Abbas Najati, Batool Noori, Choonkil Park. Asymptotic behavior of a generalized functional equation[J]. AIMS Mathematics, 2022, 7(4): 7001-7011. doi: 10.3934/math.2022389
In this paper, we investigate the Hyers-Ulam stability problem of the following functional equation
$ f(x+y)+g(x-y) = h(x)+k(y), $
on an unbounded restricted domain, which generalizes some of the results already obtained by other authors (for example [
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