4. Prove or disprove f(n) 5n3 -n3 a. O(n2) b. O(n3) c. 2(n) e.w(n) f. o(n2) Provide the appropriate C and k constants if possible. 5. Prove that (n + 5)100 - e(n100) 6. Prove transitivity of big-O: if f(n) O(g(n), and g(n) O(h(n)), then f(n) - O(h(n))