Slog for Week Nov. 10

• What we've learnt for this week?

          This week we've learnt how to prove and disprove a given function is in big-Oh and big-omega. After this week's lecture, through reading the given proof example by our instructor, I found that I clearly understand the meaning of break-even point(B) and my confuse from last two week, about how to choose B, has been solved.

          Another new concept from this week is about F (general statement about two functions). This part is very challenged for me indeed, but through instructor's note, I think I'm kind of understanding how to prove (but obviously I'm still not proficient on proving this kind of questions, thus I still need more practices).

• Confuse and challenge:

1. As I was proving Big-O, I carefully write down the statement we want to prove. Then, I realize when two functions is coinciding as variable'n'  become infinitely big, then one of the function is still in Big-O of the other function. So why? Obviously the second function is not larger than the first function anymore. 
2. One of the example question is using  limit and l'Hôpital's rule. So I'm confusing are we allow to write some scratch work about limit and l'Hôpital's rule first, then start our actual proof below it?