Strange TGraph

Dear Root users,

Sorry for my bad english but it's better that i can.

i have a question about the using of Fit mode in the TGraph.

I try to fit my data in two different way:

first - define a function : TF1 *f1 = new TF1("F1","[0]+[1]*x+[2]*x^2+[3]*x^3+[4]*x^4+[5]*x^5",0.,10.);

second way - using g1->Fit("pol5");

The function is equal in both cases, but the second interpolation is better. Why?
The second way using a spline code?

Thanks of all
Regards
Stefano Mandelli. Received on Thu Sep 17 2009 - 09:31:31 CEST