(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

if [tex]\phi[/tex] =rk/r[tex]^{3}[/tex] wherer=xi+ yJ+ zkand r is the magnitude ofr, prove that [tex]\nabla[/tex][tex]\phi[/tex] = (1/r[tex]^{}5[/tex])(r[tex]^{}2[/tex]k-3(r.k)r

Right i'm not really sure where to start here...

i know

Magnitude r = [tex]\sqrt{x^{2}+y^{2}+z^{2}}[/tex]

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Why are both r and k in vector notation?

**Physics Forums | Science Articles, Homework Help, Discussion**