Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Vector identity

  1. May 23, 2009 #1
    grad(A*B)=(A*grad)B + (B*grad)A + A curl B + B curl A

    i'm not sure how to read the RHS to begin to work out the index definition.i'm thinking if add and subtract terms this will work out. i think i can see the first two terms, but the last two maybe "A cross nabla" is what they mean acting on B componentwise, otherwise it doesnt mean anything to me.
     
  2. jcsd
  3. May 23, 2009 #2

    dx

    User Avatar
    Homework Helper
    Gold Member

    This is the correct identity:

    ∇(A⋅B) = A⋅∇B + B⋅∇A + A x (∇ x B) + B x (∇ x A)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook