Lecture
This lecture covers the concept of primitive functions, where if a function is differentiable and its derivative is the function itself, it is considered a primitive. The lecture explains how if a function has a primitive, it has infinitely many. It also discusses the relationship between two primitives of a function on an interval, highlighting the existence of a constant. Various examples of indefinite integrals of elementary functions are presented, along with techniques for calculating primitives. The lecture concludes with examples of primitive calculations using integration techniques.