1. Let f(n)-1/8n2 + 1/8. Prove f(n) is: O(n2). O(n3), (n2), and (n). 2. Let f(n) = 4-n2 + n. Prove f(n) is: Din3), 0(n*), (n3), and (1). 3. Let f(n) 3n2+4n8. Prove f(n) is O(n2). 4. Let f(n) = n!" Prove f(n) is O(n