Week 3

I was pretty confused when we were talking about converse and contrapositive. The question was if n is a multiple of four, then n^2 is a multiple of four. I got confused when the converse is if n^2 is multiple of four then n is a multiple of four because I knew that's not true since there are counter examples. The problem was solved when I realize that I have to pretend that the converse is true.. although it was painful to do so.

Another thing I found interesting was the paper folding problem.  I had a very hard time to identify if a vertex was up or down, so I had to use the data that was given on the board. The number of vertices was not that hard to find since each folds increases the number of vertices by two times, so it's going to be 2^n -1 (exclusive of the edges). However, the pattern was much harder to see and I had to guess it. Luckily, after guessing a few patterns( or seeing the hint) I saw the pattern was recursive, and each folds adds a up and down vertices besides each of every other vertices.