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Understanding vector calculus proofs

  1. Oct 1, 2011 #1
    ive been trying to understand a few of the identities my professor gave me and i can get a few of them down such as

    [itex]\nabla(\vec{A}\vec{B})=\vec{B}\nabla\vec{A} - \vec{A}\nabla\vec{B}[/itex]

    and i can break it down through cartesian and product rules but when i try to do

    [itex]\nabla X (\vec{A}ψ) = \nablaψ X\vec{A} + ψ\nabla X \vec{A}[/itex]
    where ψ is a scalar
    i get lost.

    i broke down the LHS into a matrix, and did product rule.
    but then looking at the RHS, it doesnt seem like it would come together, not unless there may be a step or a rule im overlooking. any insight?
  2. jcsd
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