Question 59
It can be shown that there exists a unique polynomial $P$ in two variables such that for all positive integers $m$ and $n$,
$$
P(m, n)=\sum_{i=1}^{m} \sum_{j=1}^{n}(i+j)^{7} .
$$
Compute $P(3,-3)$.
$$
P(m, n)=\sum_{i=1}^{m} \sum_{j=1}^{n}(i+j)^{7} .
$$
Compute $P(3,-3)$.