loop with fzero

My goal is to derive x from such equation as

for i=1:9
z(i)=fzero(@(x)gamma/(R-(1+phi(1)*x)*(1+phi(2)))-tauA2(i)-((1+alpha*beta)/beta*(gamma/x-tauA1(i))),800)
end

Here, every alphabets and matrice are 'number's. And tauA1 and 2 is [9*1] for each.

Running it, however, keeps resulting in errors saying ??? Undefined function or method 'isfinite' for input arguments of type 'sym'.

Error in ==> fzero at 333 elseif ~isfinite(fx) ~isreal(fx)

How can I get matrix x with 9*1 out of fzero?

Answer 1

[Alexander]

This works for me, if I set all variables to numbers:

 tauA1 = zeros(9, 1); tauA2 = zeros(9, 1); alpha=1; beta=2;  gamma=3; phi=[4,5]; R=6;
 z = zeros(9, 1);

 for i=1:9
  z(i)=fzero(@(x)gamma/(R-(1+phi(1)*x)*(1+phi(2)))-tauA2(i)-((1+alpha*beta)/beta*(gamma/x-tauA1(i))),800);
 end

Do you have any variables set to sym objects? If you want to use the algebraic solver, you need to call solve, like here:

 syms x;
 solve(gamma/(R-(1+phi(1)*x)*(1+phi(2)))-tauA2(i)-((1+alpha*beta)/beta*(gamma/x-tauA1(i))), x)

[Joon Jeon]

Thanks, I will try!