This lecture covers the resolution of boundary problems in one dimension, focusing on finding a function u such that u(0) = f(0) and u(1) = 0. Different models are presented, including a toy model with a plastic cord and another with an elastic cord. The instructor emphasizes the importance of not confusing one-dimensional boundary problems with other types of problems. The lecture also introduces the concept of initial value problems and discusses the role of the function C(x) in the resolution process.