{
  int n=6;
  Double_t x[10], y[10];
  int i,a;

  for(i=0;i<n;i++)
  {
      a=i-3;
      x[i]=a;
      y[i]=2*a*a+4*a+5+2*sin(i); 
  }
  
  g1=new TGraph(n,x,y);
  g1->Draw("AL*");
}