... CorporationAdvances in Difference Equations Volume 2007, Article ID 90405, 10 pagesdoi:10.1155/2007/90405 Research Article On the Stability of Trigonometric Functional Equations Gwang Hui KimReceived ... equations, ” Journal of Math-ematical Analysis and Applications, vol. 325, no. 1, pp. 237–248, 2007.[9] G. H. Kim, “A stability of the generalized sine functional equations, ” Journal of MathematicalAnalysis ... the linear multiplica-tivity of x∗in mind, for all x, y ∈ G,thedifference DA(x, y) falls into the kernel of x∗.Therefore, in view of the unrestricted choice of x∗, we infer thatDA(x, y)...