Lagrange's identity (boundary value problem)

Lagrange's identity is a mathematical concept often associated with boundary value problems and involves functions defined in a certain domain with specific conditions. It is frequently used in the context of differential equations, particularly in relation to the solutions of second-order linear differential equations. In its classical form, Lagrange's identity relates solutions of a differential equation to their Wronskian, which is a determinant used to analyze the linear independence of a set of functions.