disp('question 1) b)')
exec solLU.sci;
A=toeplitz([2 -1 zeros(1,2)])+diag([2 3 4 5])
n=4; a=-ones(3,1), b=2+[2 3 4 5]', c=a
Y=[1 1 1 1]'
X_scilab=A\Y
X_solLU=solLU(n,a,b,c,Y)