3. Show that x (x + 1) (1 x)-is the generating function for the sequence (12, 22,3,..., n?,...), and use this information to solve the difference equation [10] f(n + 1) = f (n) + (n + 1)2, f(0) = 0. 3. Show that x (x + 1) (1 x)-is the generating function for the sequence (12, 22,3,..., n?,...), and use this information to solve the difference equation [10] f(n + 1) = f (n) + (n + 1)2, f(0) = 0