How to code a math formula and passing it to a function

[Shadowrun]

hi!

I want to use a C++ function which receives a math function and executes minimization on it ( http://www.codecogs.com/d-ox/maths/o...ion/nelder.php) but I dont understand how to pass my formula as the first parameter.

There is even an example but I dont understand it...

double f(double *x) {
    double r = sqrt(x[0] * x[0] + x[1] * x[1]);
    return ABS(r) < 1E-12 ? 1 : sin(r) / r;
}

My formula is: http://personal.telefonica.terra.es/...dio1/text3.gif

This is what I've made:

for (i=1;i<=numberOfAnchors;i++)
{
   errorsquare+= pow( abs( x[i] - xestim + y[i] - yestim ) - distance[i]  ) , 2 );
}
errorsquare=errorsquare/numberOfAnchors;

Thanks.