Find O(f(n) for the given functions


(1). f(n) = 2^n + 6logn

(2). f(n) = n^3 + 42n^2 + 0n^4 + 2nlogn

(3). If f(n) = 4000 + logn

my answer is

O(2^n)

O(n^3)

O(logn)

is that correct or if you have different answer please.