double myfunction(double *x, double *par)
{ 
  double xx = x[0];
  double alpha = par[0];
  double beta = par[1]; 
  double numerator = 1+(alpha*xx)+(beta*xx*xx);
  double denominator = (x_max-x_min) + (alpha/2)*(pow(x_max,2)-pow(x_min,2)) + (beta/3)*(pow(x_max,3)-pow(x_min,3));
  double f = numerator*1./denominator;

  return f;

}


void ex8(){

double x_min = -0.95;
double x_max = 0.94;

auto c1 = new TCanvas("canvas","Example",200,10,600,400);
auto f1 = new TF1("f1",myfunction,x_min,x_max,2);
auto h1 = new TH1F("h1", "Histogram", 100, x_min, x_max);
f1->SetParameters(0.5,0.5);
h1->SetTitle("Plot of the function");
h1->FillRandom("f1",2000);
h1->Draw("");

for (int i=0;i<2000;i++){
      double kx = f1->GetRandom();
      std::cout << kx << std::endl; // for output on screen
}
}