void f1()
{
	Double_t vpi = TMath::Pi();
	Double_t pmass = 0.938272081;
	Double_t stddev = 0.000000023;
	
	TF1 *f1 = new TF1("f1","(2.0*TMath::Power([0]*[1]*[2]*[3],2))/\
	(TMath::Power(x*TMath::Sin([4]*[5]/360.0),2) + 2.0*[3]*[3]*x)", 0.0025, 1);
//	TF1 *f1 = new TF1("f1","(2.0*[0]*[0]*[1]*[1]*[2]*[2]*[3]*[3])/\
//	(x*x*sin([4]*[5]/360.0)*sin([4]*[5]/360.0) +2.0*[3]*[3]*x)", 0.0025, 1);
	f1->SetParameter(0,1.0);
	f1->SetParameter(1,1.0);
	f1->SetParameter(2,1.0/137.0);
//	f1->SetParameter(3,gRandom->Gaus(pmass,stddev ));
	f1->SetParameter(3,pmass);
	f1->SetParameter(4,10.0);
	f1->SetParameter(5,vpi);
	f1->SetLineColor(kBlue);
	f1->SetLineWidth(1);
	f1->Draw();
	TF1 *f2 = (TF1*)f1->Clone();
	f2->SetName("f2");
	f2->SetParameter(3,pmass + 100*stddev);
	f2->SetLineColor(kRed);
	cout << f1->GetParameter(3) << " " << f1->Eval(0.1) << endl;
	cout << f2->GetParameter(3) << " " << f2->Eval(0.1) << endl;
	f2->Draw(); 
}