lagrnange

%lagrnage
x=[-1;0;1;2];
y=[-2,1,3,13];
n=length(x)-1;
l=zeros(n+1,n+1);
for k=1:n+1
v=1;
for j=1:n+1
if k~=j
v=conv(v,poly(x(j)))/(x(k)-x(j));
end
end
l(k,:)=v;
end
l