% FIGURE 5.3.3
      function FUNF = FUNF533(X,K,I)
%                              INTEGRAND FOR K-TH ELEMENT OF F VECTOR
      U  = USOL(0,X,K-3,K+3);
      Ux = USOL(1,X,K-3,K+3);
      PK  = PHI(K,0,X);
      PKx = PHI(K,1,X);
      FUNF = -Ux*PKx -Ux^2*PK - U^2*PK + U*PK + PK;