Analytic soln to a 1st order nonlinera DE

Jul 2010
Hi there,
Need some help to slove the following differential equation analytically. This nonlinear 1st order DE is neither separable nor exact. I have a feeling that there may exist a integrating factor u(x,y) that will force the DE to be exact and solvable. I have tried some standard techniques to find it but no avail.

dy/dx = -(b + cosx) + (bc - asinx)/y; where a>b>0 and c is any real (preferably positive) number.

Do appreciate your help.
Thanks much.