need help with question no 16 from section 1.4

Section 1A Show directly that f(nn ).That is, use the definitions of O and S2 to show that f(n) is in both O(n3) and 2n) 16. Using the definitions of O and ?, show that 6n2 + 20n E O(n*) but 6n2 + 20n f ?(ns). 17. Using the Properties of Order in Section 1.4.2, show that 5n5 + 4n4 + 6n3 + 2n2 + n + 7 E ?(n"). 46 Chapter 1 ALOORITHMS: EFFICIENCY, ANALYSIS, AND ORDER 18. Let p(n)anin-1++n, where a0. Using the Properties of Order in Section 1.4.2, show that p(n) En) 19. The function f() 3n210n log n+1000n +4log n+9999 belongs in whi of the following complexity categories: (a) ?(Ign) (b) ?(n2logn) (e) ?(n) (e) (n2 (E) None of these (d) ?(nign) 20. The funtion f)logn)24nlogn+50 belongs in which (a) ?(ign) (b) ?((logn)") (e) e(n) (d) ?(nlgn)