Example macro showing some major probability density functions in ROOT. 
The macro shows four of them with respect to their two variables. In order to run the macro type:
  
 
void pdf002_2d_pdf() {
 
   TF2 *
f1a = 
new TF2(
"f1a",
"ROOT::Math::cauchy_pdf(x, y)",0,10,0,10);
 
   TF2 *
f2a = 
new TF2(
"f2a",
"ROOT::Math::chisquared_pdf(x,y)",0,20, 0,20);
 
   TF2 *
f3a = 
new TF2(
"f3a",
"ROOT::Math::gaussian_pdf(x,y)",0,10,0,5);
 
   TF2 *
f4a = 
new TF2(
"f4a",
"ROOT::Math::tdistribution_pdf(x,y)",0,10,0,5);
 
 
 
 
   c1->cd(1); 
f1a->SetLineWidth(1);
 
   c1->cd(2); 
f2a->SetLineWidth(1);
 
   c1->cd(3); 
f3a->SetLineWidth(1);
 
   c1->cd(4); 
f4a->SetLineWidth(1);
 
}
A 2-Dim function with parameters.
 
- Author
 - Andras Zsenei 
 
Definition in file pdf002_2d_pdf.C.