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Homework Help: Simple calculation about Magnetic induction

  1. May 10, 2017 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution

    Why does the second term become zero??
  2. jcsd
  3. May 10, 2017 #2


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    Because it does not exist. If, in the previous equation, you substitute the gradient with some vector ##\vec{V} = \vec{\nabla} \left ( \frac{1}{|\vec{x}-\vec{x}'|} \right )##, you will see why. There is no vector identity in the front of the book to be used.
  4. May 12, 2017 #3


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    The derivative ##\nabla## is with respect to ##\vec{x}##, not ##\vec{x}'##.
    Last edited: May 12, 2017
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