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Index notation

  1. May 12, 2012 #1
    Hello world,

    Index notation is driving me crazy: why on Earth is ∂_i 1/r = -x_i/r^3 ?

    I would expect it to be -x_i/r^2...

    Thanks for commenting
  2. jcsd
  3. May 12, 2012 #2


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    welcome to pf!

    hello ellocomateo! welcome to the world! :smile:

    (try using the X2 and X2 buttons just above the Reply box :wink:)

    ∂r/∂x = … ? :wink:
  4. May 12, 2012 #3
    Oh, you mean chain rule and ∂r/∂i=xi/r
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