Slog for Week9

For this week, we had term test 2, which was about 3 proofs question. Since all three questions were pretty similar to the assignments, and the proofs the professor Larry Zhang explained during the lecture, I think this was not that hard. But I still feel uncomfortable with the question 2 in the term test2, which was about the mixture of definition of limit and definition of floor function. I think it would be better to go to the office hour after I received the test back to make sure the question 2.

For the lecture, the professor went over the proofs of big oh: the proof of big oh without constant value, the proof of big oh with constant value, and the proof using limit definition. He explained how to pick the value of c and b, which I mostly feel difficulties although I still don't feel comfortable about it. Especially on the part of disproving, I do not understand why he picked the value of n as maximum of the ceiling function of '3c' and B. Since I find the same difficulty again and again, I feel I must go to the office hour to perfectly solve the difficulty I have: picking the value(I don't know why sometimes we need to pick the maximum or minimum of two given values, while sometimes we just picked one specific value.)

Moreover, we learned L'Hopital's rule for non-polynomials big-oh proof. Because I have already known this rule from the calculus, this part was quite understandable. However I feel I need lots of practices to become familiar to big-oh proofs, and should go for office hour to get the help.