how to choose the guess correctly

Hi everyone, i have a nonlinear system, but i don't be able to find the correct initial guess. There is a way to choose the inizial guess without knowing hypothetically the result?

Answer 1

[Walter Roberson]

No, not in general.

There are a lot of systems for which it is not even know whether a solution exists, so if there a way to always produce an initial guess in range, then such a hypothetical method could also be used to determine whether a solution existed or not.

You should have a look at the Global Optimization Toolbox, at the MultiStart class for one -- try a bunch of different starting locations and see if one of them works.