sequences help?

Question

given {-1/3,0/6,1/9,2/12,3/15...}
write an expression for the nth term an.

Answer 1

n-2
-----
3n

You can notice the upper part is -1, 0, 1, 2, 3, ... so it can easily be guess a(n) upper part is n-2.
Similarly, the bottom part is 3, 6, 9, 12, 15 so it's 3n.

Answer 2

(n-2)/(3n)

or ,

1/3 - 2/(3n)
which shows clearly the limit of 1/3 as n goes to infinity.

Answer 3

(n-2)/(3n) {n=1,2,3,4,5.....}