Double_t myfunc(Double_t *x, Double_t *par)
{
	Float_t z =x[0];
	Float_t d =par[0];
	Float_t D =par[1];
	Double_t f = sqrt(pow(d,2)/12+pow(D,2)*sqrt(z))*1E4;
	return f;
}
Double_t myfunc1(Double_t *x, Double_t *par)
{
	Float_t z =x[0];
	Float_t t =par[0];
	Float_t v =par[1];
	Float_t D =par[2];
	Float_t z0 =par[3];
	Double_t f = sqrt(pow(v*t,2)/12+pow(D,2)*sqrt(z)+pow(z0,2))*1E4;
	return f;
}

void posrebs2()
{
	TF1 *f1 = new TF1("f1",myfunc,0,2,2);
	f1->SetParameter(0,0.0121);
	f1->SetParameter(1,0.0158);
	f1->SetTitle("");
	f1->SetLineColor(1);
	f1->GetXaxis()->SetTitle("Drift Length [cm]");
	f1->GetYaxis()->SetTitle("#sigma [#mum]");
	f1->Draw("");
	TF1 *f2 = new TF1("f2",myfunc1,0,2,4);
	f2->SetParameter(0,0.05);
	f2->SetParameter(1,0.242);
	f2->SetParameter(2,0.0158);
	f2->SetParameter(3,0.01);
	f2->SetLineColor(1);
	f2->Draw("same");

	TF1 *f3 = new TF1("f3","f1+f2");
	f3->SetLineColor(2);
	f3->Draw("same");


}