Please help me with this

The 3D model below shows a rotated around the y-axis instead of the x-axis, from y=0 to y=9. Let's fill in this "bowl" and find the volume of the solid. To do this we will describe the solid by rotating the region between the y-axis and a around the y-a Then the cross-sections are disks (as in this animation ). For any particular y coordinate we have y = x2 , so the radius of a disk can be described using the variable y as 3 X The area of the disk at y is the function A(y) radius X Integrating all the cross-sectional areas from 0 to 9 with respect to y, we get Volume = 9 X