Question: Hey, I'd like to create a function with a solution.

Hey,

I'm on Maple 16 and looking for some help.

Basically I have a function Psi(x) and I want the function x(Psi).

Here how i define Psi(x) :

psi:=x->(ln(x)-x+k*(1-x)^2+(V*G)/(R*T)*((1-x)^(1/3)-(1-x)/2))*(R*T/V);

The constants R,V,G,T,k are well defined (physicist here).

And then if I try

solve(psi(x)=y,x);

It gives me no solutions with the warning "Warning, solutions may have been lost".

Whereas if I fsolve it for a certain y :

fsolve(-1.5e8=psi(x),x);

It gives me a numerical value.

That's fine by me, but then I want to define a function q as

q:=y->fsolve(y=psi(x),x);

It defines the function (or seems like it)

And that I cannot plot. I have the error message : Error, (in fsolve) y is in the equation, and is not solved for

Does anybody have an idea where the problem comes from ?

In case you want to reproduce, here are the values of the constants :

V:=1.8e-5;R:=8.314;T:=298;k:=0.841;G:=1e6;

Thanks a lot for any kind of help.