Using the formal definitions of Big-O show that a. n^2 + n + 11 elementof O(n^2) b. n^2 elementof O(n^2+6n) c. lg(n) elementof O(n) Using the definitions of Big-O and Ohm and theta a. Show that n^2 + 3n+ lg(n) elementof Ohm (n^2) c. Show that n^2 + 3n + lg(n) elementof Ohm (n^2) Show that n^2 + 3n+lg(n) elementof theta(n^2) Using the definitions of Big-O and o a. Show that n g o[n) using a proof by contradiction