1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Lagrange's equations

  1. Jan 16, 2016 #1
    Lagrange's equation of the first kind gives us ∂L/∂q-(d/dt)(∂L/∂q.)=Q and the Euler-Lagrange equations give us ∂L/∂q-(d/dt)(∂L/∂q.)=0 (I know the equations are not perfectly written but you get the point). How do you know which one to use?
  2. jcsd
  3. Jan 16, 2016 #2
    The second one only account for conservative forces. When you have forces that ain't conservative the right side is the sum of these forces.
    (Assuming I understood your notation correctly, been a long time since I did this)

    Edit: maybe someone else can give their input, after checking it again I suspect I may have give you a (way) too simplistic answer.
    Last edited: Jan 16, 2016
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Lagrange's equations
  1. Lagrange mesh (Replies: 2)