% FIGURE 5.8.1
      function FUNF = FUNF581(X,K,I)
      global TKP1
%                              INTEGRAND FOR K-TH ELEMENT OF "b" VECTOR
%                              (I IS NOT USED)
      OM  = OMEGA581(0,X);
      OMt = OMEGA581(0,X);
      OMx = OMEGA581(1,X);
      PK  = PHI(K,0,X);
      PKx = PHI(K,1,X);
      FUNF = exp(0.5*X^2*TKP1)*(-OMt*PK - OMx*PKx + X*TKP1*OM*PK);
