Question 475313
Not exactly sure how your equation looks like, but if it is of the form

{{{cos(theta) + j*sin(theta) = f(theta)}}},

where {{{f(theta)}}} is some expression in terms of {{{theta}}}, then you can use de Moivre's formula to "suppress" j by raising both sides to some integer power n.  The only caveat to this is, you have to make sure that 

{{{n*theta = 2k*pi}}}, for some integer k.

If {{{theta}}} cannot be written in this form then you cannot use de Moivre's theorem to "dissolve" j.