# Math Help - Vector calculus

1. ## Vector calculus

can anyone tell me how

$\epsilon \nabla \left(\frac{1}{\epsilon}\right)$

becomes

$- \ln (\nabla \epsilon)$

where $\epsilon$ can be a function of position, $\epsilon (r)$

2. nvm, sorry for your time. just use the identities

$\nabla \ln ( \epsilon) = \left(\frac{1}{\epsilon}\right) \nabla \epsilon$
$\nabla \left(\frac{1}{\epsilon}\right) = (-1/ \epsilon^2) \nabla \epsilon$