... of transformations and bordering transformations,” Bulletin of the AmericanMathematical Society, vol. 57, pp. 223–237, 1951.5 Th. M. Rassias, “On the stability of the linear mapping in Banach ... the United States of America, vol. 27, pp. 222–224, 1941.3 T. Aoki, “On the stability of the linear transformation in Banach spaces,” Journal of the MathematicalSociety of Japan, vol. 2, pp. ... 1 i/√n 1 for any n ∈{0, 1, 2, },then f is the Theodorus function.In this paper, we will adopt the idea of C˘adariu and Radu and apply a fixed point method for proving the Hyers-Ulam-Rassias...