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Zwiebach page 148

  1. Oct 21, 2007 #1
    1. The problem statement, all variables and given/known data
    Here is Zwiebach's solution to Problem 8.6.

    Can someone explain the sentence "we do not use the equations of motion".

    I used the equations of motion and I got a completely different answer!

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 22, 2007 #2
    Show what you have done.
  4. Oct 22, 2007 #3
    Sorry. I stupidly forgot to upload the attachment. Anyway above the parenthetical that says note that we do not use the equation of motion, I used the equation of motion to get

    [tex] \delta L = \epsilon \frac{d}{dt}(\frac{\partial L}{\partial \dot{q}} \dot{q} ) [/tex]

    And the rest is totally different for me.

    So, why can I not use the equation of motion here?

    Attached Files:

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