In the first place, I'm not sure whether you meant:
or
or perhaps
Even if I knew which one of these representations (and there may be others) that you meant, you failed to specify for what you wanted to solve. Do you want in terms of the other two variables, or in terms of and ? Did you want the expression evaluated at some given values of and ?
We aren't clairvoyant. You need to be more specific about what you want.
