Volume of Solids of Revolution Disk Method

Volume of solids of revolution is another application of the definite integral.
If the area bounded by the function and the x -axis is rotated around the x-axis, the vertical rectangles used to find the area become vertical disks which are used to find volume. In the same way, when the area bounded b;y a function and the y axis is rotated about the y-axis, the horizontal rectangles used to find the area become flat disks which are used to find volume.