Here you go:

Thank you very much for trying to help! Sorry I'm new to the forum and don't know how I can attach files. But here's the loop: for A from 12 to 20 do ans := fsolve({f1 = 0, f2 = 0, f3 = 0, f4 = 0, f5 = 0}, {f = 0 .. 1, k = 0 .. 100, l = 0 .. 1, w = 0 .. 100, theta = 0 .. 1}); eval(phi, [k = ans[2], l = ans[3], f = ans[1]]) end do;

I have a non-linear system of 5 equations (thus 5 solutions of course) which I'm trying to solve for very specific parameter values, therefore the "fsolve" is inside a loop.

How would I go about using the solutions at each iterations to evaluate another function?

I tried the solution above and it doesn't seem to work, I still get the equation back in analytical form without a numerical evaluation.

Any help is much appreciated!