I need some help in trying to solve a equation in the form of P[V,T]= V^2* T + V*T + T , I have a data set that I am trying to match this

myFit = NonLinearModel.fit(mv,t , 'psi ~ (X(1) + X(2).*T + X(3).*T.^2) + (X(4)+X(5).*T + X(6).*T.^2).*V + (X(7)+ X(8).*T + X(9).*T.^2).*V.^2',[0 0 0 0 0 0 0 0 0 ]);

I don't see how to set up the nonlinear mulivariable equation. I see examples that are close to the above.

I am looking to solve and optimize this equation as close to close to R^2 = 1 as I can get. Just need the coefficients and a way to adjust them to meet different applications as a function of many inputs.

Changing the equation could be an option as well... Any help would be great

Is there a way to make this into a DLL after completion....

Thanks

Phil