Question

what is variational principle

Answer 1

A variational principle is a scientific principle used within the calculus of variations, which develops general methods for finding functions which extremize the value of quantities that depend upon those functions. For example, to answer this question: "What is the shape of a chain suspended at both ends?" we can use the variational principle that the shape must minimize the gravitational potential energy.

Answer 2

Variational principle is the scientific principle used within the calculus of variations, which develops general method of finding functions which extremeize the value of quantities that depends on those functions