function z_2 = integrand_2(x,y)
  global  h x_min x_max y_min y_max
  
%%    For Q = A^(-1) case
  %z_2 = (y_max+h-y).*(x_max+h-x).*Green(x,y);
  
%%    For Gaussion case
  Sigma = 1/2^10;  
  z_2 = (y_max+h-y).*(x_max+h-x).*exp(-(x-y).*(x-y)./(2*Sigma^2));