Stability and non-stability of generalized radical cubic functional equation in quasi-β-Banach spaces.

The object of this paper is to solve the generalized radical cubic functional equation, and discuss the stability problem in quasi-β-Banach spaces and then the stability by using subadditive and subquadratic functions in (β; p)-Banach spaces for the generalized radical cubic functional equation. Also certain non-stability results are investigated via specific counterexamples. Our results are generalization of the main results which are established by Z. Alizadeh and A. G. Ghazanfari in 2016. [ABSTRACT FROM AUTHOR]