This lecture covers the resolution of simple trigonometric equations involving tangent and cotangent functions, as well as the definitions of arctangent and arccotangent functions. The instructor explains how to find solutions to equations like tan(a) = c and cot(a) = c, and provides examples to illustrate the concepts. The lecture also delves into the equation Asin(a) = Bcos(a) and its resolution. By the end of the lecture, students will have a solid understanding of these trigonometric functions and how to solve related equations.