Ok my book has this question f(y)= 4y-y^2 for the interval 1<(or equal to) y<or equal to ) 2

I have to find the approximate area of the region between the graph and the y-axis using the limit process

I've only done these area problems with x. Is it the same process with y? Or do i have to change it? I vaguely recall an extra step somewhere, but have no clue what it is.

thanks in advance