Use the limit method to prove the asymptotic relation between these 3 functions:
n
2n
n^2
The limit method says that: lim (n --> infinity) f(n) / g(n) tends to 0, then f(n) = o(g(n)). Similarly, if the limit tends to infinity, then f(n) = small omega (g(n)), and if the limit tends to a constant, then f(n) = theta (g(n)).