code 41760;
real procedure BETADENS(X,ALPHA1,ALPHA2);
value X,ALPHA1,ALPHA2; real X,ALPHA1,ALPHA2;
begin real BET;

  if ALPHA1 ≤ 0
  then STATAL3 ERROR(“BETADENS”,2,ALPHA1);
  if ALPHA2 ≤ 0
  then STATAL3 ERROR(“BETADENS”,3,ALPHA2);
  
  if X ≤ 0 ∨ X ≥ 1 then BETADENS:= 0 else
  begin BET:= EXP(LOGGAMMA(ALPHA1 + ALPHA2) -
                  LOGGAMMA(ALPHA1) - LOGGAMMA(ALPHA2));
      BETADENS:= BET × EXP((ALPHA1 - 1) × LN(X) +
                    (ALPHA2 - 1 ) × LN(1 - X))
  end;
end BETADENS;
eop