a Department of Basic Technology, Applied Mathematics and Physics, Yamagata University, Yonezawa 992-8510, Japan b Department of Mathematical Sciences, Faculty of Science, Shinshu University, Matsumoto 390-8621, Japan
Abstract:
We give the solution of the functional equation f(x+y)+λf(x)f(y)=Φ(x,y) under some conditions. Also we show its Hyers-Ulam stability.