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Mathematical subject classification-39B72, 47H09
In this paper, the stability of cubic functional equation f (kx + y) − f (x + ky)=(k −1)(k +1) 2[f (x) − f (y)] − k(k −1) f (x − y) (where k is a positive integer greater than 2) using direct and fixed point method in random normed spaces has been proved.
Hyers-Ulam-Rassias stability, cubic functional equation and random normed spaces