test1

function ans=lagranges(xxx,yyy,xx)
coeficients=zeros(array(xxx),array(xxx));
for i=1:array(xxx)
    poly=1;
    denominator=1;
    for j=1:array(xxx)
        if j~=i
           poly=conv(poly,[1 -xxx(j)]);
           denominator=denominator*(xxx(i)-xxx(j));
        end
end
    coeficients(i,:)=poly/denominator;
end
if integrand==1
   ans=coeficients;
elseif integrand==2
    ans=yyy*coeficients;
else
    ans=polyval(yyy*coeficients,xx);
end