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Feynman Lectures Volume 3 Equation 9.41

  1. Jan 30, 2013 #1
    I don't understand how the last equation in the attached picture is derived from equations 9.40 and 9.39, can anyone help?
     

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  3. Jan 30, 2013 #2

    Simon Bridge

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    Do the substitution as described and use the fact that ##\mu\epsilon## is small compared with ##A##.
    The last equation is for the LHS only of eq.9.39 ... where ##C_I## is given in the first equation in 9.40.
     
    Last edited: Jan 30, 2013
  4. Jan 30, 2013 #3
    Oh, I got it. Tx
     
  5. Jan 30, 2013 #4

    Simon Bridge

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    No worries - the RHS in the last equ. looks a lot like the RHS in equ.9.39 so I expect that's what threw you. I suspect that Feynman exploits the similarity on the next page.
     
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