- #1
daudaudaudau
- 302
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Hi.
In http://www-personal.umich.edu/~pran/jackson/P505/p1s.pdf" solution(page 2) to Jackson 1.5 it is stated that
[tex]\nabla^2 \left(\frac{1}{r}\right)=-4\pi\delta^3(\mathbf r)[/tex].
But why is this true?
[tex]\nabla^2\left(\frac{1}{r}\right)=\frac{1}{r^2}\frac{d}{d r}\left(r^2\frac{d}{dr}\frac{1}{r}\right)=\frac{1}{r^2}\frac{d}{dr}(-1)[/tex]
In http://www-personal.umich.edu/~pran/jackson/P505/p1s.pdf" solution(page 2) to Jackson 1.5 it is stated that
[tex]\nabla^2 \left(\frac{1}{r}\right)=-4\pi\delta^3(\mathbf r)[/tex].
But why is this true?
[tex]\nabla^2\left(\frac{1}{r}\right)=\frac{1}{r^2}\frac{d}{d r}\left(r^2\frac{d}{dr}\frac{1}{r}\right)=\frac{1}{r^2}\frac{d}{dr}(-1)[/tex]
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