Department of Mathematics, Kangnam University, Yongin, Gyoenggi 446-702, Republic of Korea
Copyright © 2010 Gwang Hui Kim. This is an open access article distributed under the
Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
We will investigate the superstability of the sine functional equation from the following Pexider-type functional equation (), which can be considered the mixed functional equation of the sine and cosine functions, the mixed functional equation of the hyperbolic sine and hyperbolic cosine functions, and the exponential-type functional equations.