  We calculate the three-point functions in the sine-Liouville theory
explicitly. The same calculation was done in the (unpublished) work of Fateev,
Zamolodchikov and Zamolodchikov to check the conjectured duality between the
sine-Liouville and the SL(2,R)/U(1) coset CFTs. The evaluation of correlators
boils down to that of a free-field theory with a certain number of insertion of
screening operators. We prove that the winding number conservation is violated
up to (+-)1 in three-point functions, which is in agreement with the result of
FZZ that in generic N-point correlators the winding number conservation is
violated up to N-2 units. A new integral formula of Dotsenko-Fateev type is
derived, using which we write down the generic three-point functions of
tachyons explicitly. When the winding number is conserved, the resultant
expression is shown to reproduce the correlators in the coset model correctly,
including the group-theoretical factor. As an application, we also study the
superstring theory on linear dilaton background which is described by
super-Liouville theory. We obtain the three-point amplitude of tachyons in
which the winding number conservation is violated.
