I use very often the onboard solver of EXCEL (grg nonlinear) and I am quite happy with its performance. Since I use the data generated by the solver for further calculations I would like to knwo the machine epsilon (error of my result). Is there a way of estimating it or does the solver reports it and I have not been able to find it in the reports?

The formulae which I minimize by altering R_18 is

```
min=-3*K*(R_18)^\lambda+2*K*R_45*R_18^\lambda+s*R_18-R_46
```

All other quantities are known.