| March 13 |
I had a question about the setup of problem 1. I know we can’t assume anything about the direction/orientation of the dipole, but may we place the center of the dipole at a favorable position (e.g., along the polar axis defined by our coordinate system)?
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The answer you need is "coordinate free" , that is it is a vector expression. You may use any coordinate system as long as your answer does not depend on any coordinates, but it should not be necessary.
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| Apr 5 |
In problem 3.16(c), for the third identity, rho can be real or imaginary?
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No. rho is real. But when you take a limit, you can take a limit any way that you want. Rho appears in the final expression, so you are not taking a limit of rho. The quantity you are taking to a limit may be real or imaginary.
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