Can I use multiple equation in Cftool?

I'm learning to use cftool and i want to use "Custom Equation" and I already know how to use it.

but the value of my function is not always the same.

I have this:

    fk=sign(qp)*fc+fv*qp;

    if qp == 0

      if abs(tao)< fs

        fq = tao;

      else

        fq = fs * sign(tao);

      end

    else

      fq = fk;

    end

For the first function I use this:

sign(x)*a+b*x;

And It works. But how can i use "if" or adjust my function to the different parameters?

Answer 1

[Matt J]

No. You have more flexibility with LSQCURVEFIT. However, either of these toolbox functions are overkill for the equations you've shown. They are linear w.r.t the unknowns "a" and "b", so just use a linear least square solver (e.g., backslash) to solve for them.