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i am desperate about the expansion of the following equation:

[tex]\nabla ( \hat{r} /r^2 \cdot \vec{p}(t_o))[/tex]

where [tex]t_o[/tex] is the retarded time at the center

[tex]t_o=t-r/c[/tex]

and [tex]\vec{p}(t_o)[/tex] is the electric dipole moment at [tex]t_o[/tex]

actually, it expands to 4 main parts and i am unable to figure out the last one, namely:

[tex]\hat{r} /r^2 \times (\nabla \times \vec{p}(t_o))[/tex]

it would be magnifique if anyone can figure out the expansion of that term

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# Homework Help: Gradient equation with retarded time

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