Generalized Hyers-Ulam Stability for a General Mixed Functional Equation in Quasi-β-normed Spaces

摘要

In this paper, we establish the general solution and investigate the generalized Hyers-Ulam stability of the following mixed additive and quadratic functional equation f(lx + y) + f(lx - y) = f(x + y) + f(x - y) + (l- 1)[(l+2)f(x) + lf(-x)],f(lambda x + y) + f(lambda x - y) = f(x + y) + f(x - y) + (lambda - 1)[(lambda +2)f(x) + lambda f(-x)],