// construction de la matrice aij

function [A] = initialiserMatriceA(n)

A=zeros(n,n);

for i=1:n-1
  A(n,n) = 2;
  A(i,i) = 2;
  A(i,i+1) = -1;
  A(i+1,i) = -1;

end

endfunction
