{
    
  
    TF1 *f1 = new TF1("f1","1-x",0,10);
    f1->SetParameter(0,2); 
    f1->Draw(); 
   
    

    TF1 *f2 = new TF1("f2","gaus(x)",0,10);
    f2->SetParameter(0,2);
    f2->SetParameter(1,4);
    f2->SetParameter(2,2.5);
    f2->Draw();
    
    cout<<f2->GetParameter(2)<<endl;

    
    TF1 *f3 = new TF1("f3","f1+f2",0,10);
    f3->Draw();
    f3->SetParameter(0,3);
    f3->SetParameter(2,0.5);
    f3->Draw();
    f1->SetLineColor(kBlue+2);
    f1->Draw("same");
    
   
  
    f2->SetParameter(0,3);
    f2->SetParameter(2,0.5);
    f2->Draw("same");
   
}