Hi,

I am trying to solve a complex non-linear equation through the command “fsolve” in OCTAVE but I can’t figure out how the problem should be correctly defined.

In details, I have a function f(p1,…,pn | ZZ) depending on some known real parameters (p1, …, pn) and a complex variable (ZZ). I am looking for an approximated solution of the equation f=0 for several combinations of the parameters.

I guess the command “fsolve” could be the one to be used but I can’t get any meaningful solution. I tried to go through the manual but I didn’t work it out.

```
eq = @(ZZ) (coth(pi*(ZZ)*l_1/L) + coth(pi*(ZZ)*l_2/L) + pi*(ZZ)/L*M/m*(1+2*xd*(ZZ)/k)/(1+2*xd*(ZZ)/k+((ZZ)/k)^2));
XX = fsolve (eq, 0.0001+0.0001*i, optimset ("ComplexEqn", "on"));
```

Could you please help me with this?

Thanks