Variational Calculus: Euler-Lagrange vs. Lagrange's Equation of Motion

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SUMMARY

The discussion clarifies the relationship between the Euler-Lagrange equation and Lagrange's equations of motion, asserting that they are fundamentally the same equations but are named differently based on their context. The distinction lies in the application, where Euler's equations are more general, while Lagrange's equations pertain specifically to physics. Additionally, the concept of Lagrangian density is introduced as a volumetric representation of the Lagrangian, relevant in the context of classical field theory.

PREREQUISITES
  • Understanding of variational calculus principles
  • Familiarity with Lagrangian mechanics
  • Knowledge of classical field theory concepts
  • Basic grasp of action integrals in physics
NEXT STEPS
  • Study the derivation of the Euler-Lagrange equation in variational calculus
  • Explore Lagrange's equations of motion in the context of classical mechanics
  • Investigate the role of Lagrangian density in field theory
  • Learn about action integrals and their applications in physics
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Students and professionals in physics, particularly those focusing on mechanics and field theory, as well as mathematicians interested in variational calculus.

babtridge
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Could someone please direct me to a good web page or comment on the main difference between the euler lagrange eqn and lagranges eqn of motion. I'm struggling to differentiate between the two...
Also, I'm struggling to grasp the concept of Lagrange density - when does one introduce this into the action integral? :confused:

Cheers
 
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Well,technically,they are the same bunch of equations.The names are confusing.It would be fair,if the general ones,which don't have anything to do with physics,Lagrangians and lagrangian actions be called :"Euler's equations".

And the ones who do have everything to do with physics:"Lagrange's equations".

Daniel.

P.S.The Lagrangian density is the volumic density of lagrangian.Thay appear once people introduce the concept of (classical) field.
 

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