Variational Calculus is a branch of mathematics that deals with finding the extrema (maximum or minimum values) of functionals, which are mappings from a set of functions to real numbers. It is often used in physics and engineering to solve problems involving optimization, such as determining the shape of a hanging cable or the path of a moving object. The fundamental principle of Variational Calculus is the Euler-Lagrange equation, which provides a method to derive the equations of motion for systems. This approach is essential in fields like classical mechanics, economics, and control theory, where optimizing a certain quantity is crucial for effective decision-making.