A practical proposal to obtain solutions of certain variational problems avoiding Euler formalism

Heliyon. 2020 Apr 1;6(4):e03703. doi: 10.1016/j.heliyon.2020.e03703. eCollection 2020 Apr.

Abstract

The aim of this article is to show the way to get both, exact and analytical approximate solutions for certain variational problems with moving boundaries but without resorting to Euler formalism at all, for which we propose two methods: the Moving Boundary Conditions Without Employing Transversality Conditions (MWTC) and the Moving Boundary Condition Employing Transversality Conditions (METC). It is worthwhile to mention that the first of them avoids the concept of transversality condition, which is basic for this kind of problems, from the point of view of the known Euler formalism. While it is true that the second method will utilize the above mentioned conditions, it will do through a systematic elementary procedure, easy to apply and recall; in addition, it will be seen that the Generalized Bernoulli Method (GBM) will turn out to be a fundamental tool in order to achieve these objectives.

Keywords: Euler equations; Mathematics; Ordinary differential equations; Variable end point conditions; Variational problems.