Cones and Cylinders: Geometric Definitions

This lecture covers the geometric definitions of cones and cylinders, including the concept of generatrices, bases, and surfaces of revolution. It explains how cones and cylinders are sets of lines in space, with cones passing through a point and cylinders being generated by lines parallel to an axis. The lecture also discusses the construction of cones and cylinders based on different base curves, such as circles and cerdes, and the properties of tangents and tangent planes to these surfaces.