Let f(n) = 5n2 + 8n + 3. Show that f(n) is O(n2). Be sure to…

Let f(n) = 5n2 + 8n + 3. Show that f(n) is O(n2). Be sure to specify the values of the witnesses C and k.(Please note: For all the questions in this exam, show all the necessary steps for each question to get the full points for the question, otherwise providing just the answer does not attract any points without providing the complete proof, or computation or justification of all the steps of your solution.) 

Each user has a pin 4 characters long where each character i…

Each user has a pin 4 characters long where each character is an uppercase letter, a lowercase letter, or a digit. Each password must contain at least one digit. How long will it take (these are, units of time) to check every possible character combination, if each check takes one unit of time, justify your answer.(Show all your computations to get the full points for the question).