Washer method or shell method? This Woody Calculus lesson teaches the Calculus 2 decision rule for volumes of revolution: identify the function form, check the axis of rotation, choose the right slice, and build the correct volume integral.
Gabriel’s Horn is one of the most unforgettable paradoxes in Calculus 2: a solid with finite volume but infinite surface area. Learn how the disk method gives volume π, while the surface area integral diverges using improper integrals and comparison.

