1. The problem statement, all variables and given/known data Hello, This is a 2 part question I guess. In general math, you form a sort of equality by doing to one side what you do to the other, meaning if you add 3 to one side, you add 3 to the other. In this example, you have to put a 2 on the right side, but then you put a half on the other, why is that? Why isn't it 2 on both? Second question is where did the one fourth come from? (1/4th) on the second line. I thought that the derivative of the function (2 dx) later drops out of the final equation, but here it drops out and a fourth replaces it apparently, how/why did this happen? 2. Relevant equations 3. The attempt at a solution Its already solved, I just need an explanation of how it came to be.