= 2. Prove the following using the definitions of 0, 12, and O. (a) n2 + 3n 20 = O(na) (b) n 2 = 12(n) (c) log10 n +4 = O(log2 n) (d) 2n+1 = O(2") (e) Inn = O(log2 n) (f) n = N2(lg n) for any e > 0 = =