فهرست نشریات علمی دسترسی آزاد ایران

Let $ \mathcal{A} $ be a Banach algebra, $ x,y\in  \mathcal{A}  $ and $ \varphi,\psi: \mathcal{A} \rightarrow  \mathcal{A}  $ be two additive mappings. In this paper, we solve    \begin{align*}        \begin{cases}            &2\varphi(x+y)=\psi(x-y),\\            &\psi(x+y)=2\varphi(y-x)+4\varphi(x).        \end{cases}    \end{align*}Also, we investigate the Hyers-Ulam stability of the system of additive functional equations in complex Banach spaces. Furthermore, we prove the Hyers-Ulam stability by fixed point method in Banach algebras.