We obtain the Hyers-Ulam-Rassias stability of a betatype functional equation $f(varphi(x),phi(y))$ = $ psi(x,y)f(x,y)+ lambda(x,y)$ with a restricted domain and the stability in the sense of R. Ger of the equation $f(varphi(x),phi(y))$ = $ psi(x,y)f(x,y)$ with a restricted domain in the following settings: $g(varphi(x),phi(y))-psi(x,y)g(s,y)-lambda(x,y)$mid$leqvarepsilon(x,y)$</TEX> and $frac{g(varphi(x),phi(y))}{psi(x,y),g(x,y)}-1 $mid$ leqepsilon(x,y)$</TEX>.