Apply the formal definition of Big-O notation to prove each of the following upper bounds. Remember to be clear and specific about your choices for the constants c and n0 that will make your solution work.

3A

Prove that f(n) = n^3 + 20n + 1 is O(n^3)

3B

Prove that f(n) = n^2 + 2n + 1 is O(n^2)