On stability of a cubic functional equation in intuitionistic fuzzy normed spaces

In this paper, we determine some stability results concerning the cubic functional equationf(2x+y)+f(2x-y)=2f(x+y)+2f(x-y)+12f(x)f(2x+y)+f(2x-y)=2f(x+y)+2f(x-y)+12f(x)in intuitionistic fuzzy normed spaces (IFNS). We define the intuitionistic fuzzy continuity of the cubic mappings and prove that the existence of a solution for any approximately cubic mapping implies the completeness of IFNS.