Solids of revolution - Disk integration

Explore solids of revolution formed by revolving a plane region about the x-axis or the y-axis. Move the green points, and use the sliders to select which solid you want to explore. Use the angle slider to rotate the region manually, or select Rotate! in the drop-down list. Drag the 3D View to explore the solid from different points of view. The current value of the volume is displayed only for revolutions about the x-axis.