Euler lagrangian equation associated with the variation of a given functional

[Raha]

Hi All,

is there anybody to give me some help on how I can calculate the Euler Lagrangian equation associated with variation of a given functional?
I am new with these concepts and have no clue about the procedure.

thanks a lot

 

[WannabeNewton]

http://en.wikipedia.org/wiki/Euler_lagrange_equation