Ok, I was thinking today during my calculus class about taking the integral of a function in a different way. Let's assume for a second that we want to find the area between the function and the y axis, on the interval x = [0, 2] of the function y = 2x. What I was thinking I could do, is take the integral of y. (y^2)/2 then substitute 2x in for y, since y = 2x. (2x)^2 / 2 That would give us the integral between the function and the y axis and we would be able to put in the interval for x. But it didn't work... I got the wrong answer? Why doesn't this work? I think it should work. Thanks.