kill(all)$

van=facebook.com/LearningCalculus$

f(x,y):=limit((x^(n+1)+y^(n+1))/(x^n-y^n),n,inf);

check(x,y):=x^n-y^n$

A:ident(10)$

for i:1 thru 10 do
    for j:1 thru 10 do
        if(check(i,j) # 0) then
            A[i,j]:f(i,j)
        else
            A[i,j]:und$

A;