Originally Posted by

**Ackbeet** Hmm. Given the extreme complexity of your equations, I quite doubt that anyone here on MHF is going to take the time to slog through it all. I can tell you this: in Mathematica, the commands you'd probably use might look something like this:

epsilon = ...

R = ...

L = ...

Solve[{D[L,x]==0,D[L,y]==0,D[L,z]==0,D[L,T4]==0},{x,y,z,T4,q}]

I do have one question: it does not seem to me that you have enough equations to solve for all five variables. I see four equations - the ones involving the derivatives. That is, you'd plug in the definitions of epsilon and R into the L equation. So that's essentially one equation defining L. But L is really an "unknown", so that doesn't help you get down to the five variables you're after. Then, you impose the four derivative conditions, so that's four equations. Your "fifth" equation is merely a restatement of the definition of epsilon, so it doesn't add any new information. You might be able to solve parametrically for your variables, but that's about it, unless you've got another equation up your sleeve that you didn't give us.