Hi everybody,(adsbygoogle = window.adsbygoogle || []).push({});

I'm preparing myself for the introduction to electrodynamics course and thus I

go through vector analysis, but I hardly understand a problem given in my book

(Griffiths, Introduction to Electrodynamics 3rd edition, page 18, Problem

1.16):

I have to calculate the divergence of the following function:

see pic 1

Ok my problem is, I can't figure it out how the author calculates the result of it. He has the following approach...see pic 2 (between del and v should be a dot, cause it is meant to be the dot product, not the cross product!!)

OK...so far, so clear...I understand this step but now, he goes ahead by taking x^2+y^2+z^2 to the power of -3/2. Why?? Where does this fraction of -3/2 comes from? Is there any rule I didn't know?

Anyway, thanks a lot in advance. Have a nice day...sincere greetings from Berlin, Germany

Daniel Jackson

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# Vector Analysis

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