  In the present paper we deal with the following generalization of the
sine-cosine equation \begin{equation*} \int f_1(x+y-t)+f_2(x-y+t)
d\mu(t)=g(x)h(y) \end{equation*} for complex valued functions $f_1$, $f_2$, $g$
and $h$ defined on a commutative topological group $G$, where $\mu$ is a
complex measure defined on $G$.
