#include "TF1.h"
#include "TMath.h"

Double_t myfunction(Double_t *x, Double_t *par)
   {
      Double_t xx =x[0];
      Double_t f;
      if (xx!=0.) {
        f = TMath::Abs(par[0]*TMath::Sin(par[1]*xx)/xx);
      } else {
        f =0.;
      }
      return f;
   }

void tf1_problem()
{
  Double_t ptmmax[2],par[2];
  Double_t yval;

  TF1 *fb = new TF1("fbb",myfunction,0.001,10.,2);
  fb->SetParameter(0,1.);
  fb->SetParameter(1,1.);
  fb->Draw();

  ptmmax[0]=2.0;
  par[0]=1.0;
  par[1]=2.0;
  fb->InitArgs(ptmmax,fb->GetParameters());
  yval=fb->EvalPar(ptmmax,0);
  cout<<yval<<endl;
  yval=fb->EvalPar(ptmmax,par);
  cout<<yval<<endl;
}