  We consider a Langevin equation with variable drift and diffusion
coefficients separable in time and space and its corresponding Fokker-Planck
equation in the Stratonovich approach. From this Fokker-Planck equation we
obtain a class of exact solutions with the same spatial drift and diffusion
coefficients. Furthermore, we analyze some details of this system by using the
spatial diffusion coefficient $D(x)=\sqrt{D}|x| ^{-% \frac{\theta}{2}}$.
