Hello, here is my problem.[/PLAIN] [Broken](adsbygoogle = window.adsbygoogle || []).push({});

http://imgur.com/VAu2sXl

My confusion lies in, why those particular partial derivatives are chosen to be acted upon the auxiliary function and then how they are put together to get the Euler-Lagrange equation?

My guess is that it's related to the turning points of the auxiliary equation, however i don't know why those derivatives are chosen and how they're related to the EL equation.

Sam

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Calculus of variations

**Physics Forums | Science Articles, Homework Help, Discussion**