MATLAB: Can one use fsolve with symbolic value equations

fsolvesymbolic

Hello everyone. I am wondering if in Matlab, one can use symbolic variables together with fsolve. I have to equate a gradient (calculated from substituted variables) to zero. Here is what I tried. Could anyone tell me what is wrong with this? If I can't use fsolve with symbolic value equations, how could I solve for 2 nonlinear symbolic valued equations with two unknowns? Tks:
function gradB = myfun(X)
syms X(1) X(2) n m
B = subs(X(1)+ X(2), [X(1), X(2)], [n+m, n-m]);
gradB = gradient(B, [n, m])
Script
X0 = [...];
fhandle = @myfun;
X = fsolve(fhandle, X0)

Best Answer

It’s a bit difficult to follow what you’re doing, but if you want to use symbolic expressions and you don’t mind slow code, use the solve function.
the fsolve function will find the values where the argument function equates to zero, so if you want to do the same with your symbolic gradient, my answer to Finding the null gradient directly applies to your problem.
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