Well, over this interval from y one to y two, our blue function, f of y, takes on larger x values than g of y. So this length right over here, this would be f of y, f of y, this x value, minus this x value, minus g of y. So this is going to be f of y minus g of y, g of y. Well, we know what f of y and g of y are. Really, the trickiest part is is figuring out these points of intersection. So let's think about where these two curves intersect. They are both equal to x, so we can set these two y expressions equal to each other.