If the nth partial sum Sn of an infinite series n - 5 1 . an = 50-1 E an O 2. an An - 5 = n =1 5n is given by O An - 5 3. an = 2 n 5n Sn = 2 - En 6n - 5 find an for n > 1. 4. an = 5n O n - 5 5 . an = 2 50-1 O 6n - 5 6. an = 2 5n