I am asked to show that http://s3.amazonaws.com/answer-board...3950009460.gif. I know that http://s3.amazonaws.com/answer-board...5825005037.gif and that http://s3.amazonaws.com/answer-board...1450006019.gif but from there, I get stuck because if I'm looking at y = 1, wouldn't the norm always be the same... ? I'm not sure what I'm missing, any help would be greatly appreciated!!!