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Homework Help: Classical mechanic transformation

  1. Sep 9, 2015 #1
    Hello everyone, I have a little problem with some transformation.
    I wonder how i can get that result. Can somebody explain it step by step?
    The " ' " means derivative. Thank you for your time ;)
  2. jcsd
  3. Sep 9, 2015 #2


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    Try starting with a really simple case, like if you have just ## x_1 = f_1(q_1,q_2)## and ## x_2 =f_2(q_1,q_2)##. You can work out each term in the resulting Lagrangian in this case and that may help you see how it works in general.
  4. Sep 9, 2015 #3
    As Geofleur said start with the simplest but non trivial case, then step it up a little bit, you'll see the pattern right away and convince yourself of the general formula.
  5. Sep 11, 2015 #4
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