% FIGURE 5.11.1
      function FUNB = FUNB5111(X,K,I)
%                              INTEGRAND FOR (K,I)-TH ELEMENT 
%                              OF "B" MATRIX 
      PK = PHI(K,0,X);
      PI = PHI(I,0,X);
      FUNB = exp(-2*X)*PK*PI;