I have some very complicated expressions in the form of F[x,y,z,A,B,C]/(x^2 - y^2 - z^2) . Here F[ ] is a very long function of x,y,z as well as some other terms, A,B,C. There are places in F where (x^2 - y^2 - z^2) could be completely canceled out, however, no matter what algebraic manipulation I try in mathematica (Simplify,Cancel,Factor, etc), I cannot get these terms to cancel!
What I want is a way to say: rewrite F in terms of groupings of (x^2 - y^2 - z^2) wherever you can
(even if it makes F look overall messier). Note I've tried "Collect" and doesn't seem to work in this sense.
Can anybody suggest a good thing to try? I can send the expression for F in a notebook, but I warn you it's very VERY long