Calculating Volume Of a Region via Washer
Calculate the volume obtained by rotating the region in the first quadrant bounded by x2+y2=0, y=x, and x=0.
I understand how to use shell method with this question (radius: x, height: (1-x2)1/2-x, bounds: 0 to sqrt2/2), with the answer being 2∏/3-∏sqrt2/3. How would you calculate this using washer/disk method however? I tried using bounds [0,sqrt2], but I don't come out with the correct answer.
Another side note, when do you use dy versus dx. I understand dx is taking vertical slices and dy is taking horizontal slices perpendicular to the y axis?