void function() {
  TCanvas *c1 = new TCanvas("c1","The FillRandom example",200,10,900,400);
  c1->Divide(3,1);

  c1->cd(1);
  TF1 g("g","gaus(0)+pol0(3)",-10,10);
  g.Draw();
  g.SetParameter(0,100);
  g.SetParameter(1,0);
  g.SetParameter(2,1);
  g.SetParameter(3,10);
  g.DrawCopy();

  c1->cd(2);
  TFormula ff("ff", "100*abs(sin(x)/x)");
  TF1 h("h","g+ff",-10,10);
  h.DrawCopy();

  c1->cd(3);
  form1 = new TFormula("form1","abs(sin(x)/x)");
  sqroot = new TF1("sqroot","x*gaus(0) + [3]*form1",0,10);
  sqroot->SetParameters(10,4,1,20);
  sqroot->Draw();
}