The picture is found here (top picture):
The Attempt at a Solution
I get the wrong sign (ie: negative area) when I integrate to find the area between 2 curves when I integrate with respect to the y-axis (ie: when I use dy). So since my area is negative, I must be subtracting the wrong curve from the other curve (ie: instead of F-G, it should be G-F). Should it be [(top curve)-(bottom curve)] ? That's what I did, but it appears that [(bottom curve)-(top curve)] gives the correct answer. By the way, my work (attached pict) also shows me using dx just to prove to myself that it works, which it did. Thanks for any logic help.