- #1

emroz92

- 12

- 1

[itex]\oint\oint\frac{d\vec{l_{1}}\cdot d\vec{l_{2}}}{r}[/itex],

where [itex]r[/itex] is the distance between the length elements [itex]\vec{dl_{1}}[/itex] and [itex]\vec{dl_{2}}[/itex].

Is this integral always positive? If so, what would be the mathematical treatment associated to prove its positivity?