Question

Hi guys . is there anyone who can solve this step by step.​

Answer 1

F(n + y, n - y) = 2ny

We can write n = n + y - y, and y = n - (n - y), so that

F(n + y, n - y) = 2(n + y - y)(n - (n - y))

==> F(n, y) = 2(n - y)(n - y) = 2(n^2 - y^2)