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2.4 Verschiedene Beziehungen des Ortsvektors

Sei $ \vec{r}\,$ ein Ortsvektor der Länge r vom Ursprung zu (x, y, z) und sei $ \vec{J}\,$ ein beliebiger konstanter Vektor. Dann gilt

$\displaystyle \nabla$ . $\displaystyle \vec{r}\,$ = 3 (2.26)

$\displaystyle \nabla$ x $\displaystyle \vec{r}\,$ = 0 (2.27)

$\displaystyle \nabla$$\displaystyle \vec{r}\,$ = $\displaystyle {\vec{r} \over {\vert r\vert}}$ (2.28)

$\displaystyle \nabla$$\displaystyle {1 \over {\vert r\vert}}$ = $\displaystyle {{-\vec{r}}\over {\vert r\vert}}$ (2.29)

$\displaystyle \nabla$ . $\displaystyle {{\vec{r}}\over {\vert r\vert^3}}$ = - $\displaystyle \nabla^{2}_{}$$\displaystyle {1 \over {\vert r\vert}}$ = 0      $\displaystyle \mbox{wenn $r \neq 0$}$ (2.30)

$\displaystyle \nabla$ . $\displaystyle {{\vec{J}} \over r}$ = $\displaystyle \vec{J}\,$ . ($\displaystyle \nabla$$\displaystyle {1 \over r}$) = - $\displaystyle {{(\vec{J}\cot \vec{r})}\over {\vert r\vert^3}}$ (2.31)

$\displaystyle \nabla^{2}_{}$$\displaystyle {{\vec{J}}\over {\vert r\vert}}$ = $\displaystyle \vec{J}\,$$\displaystyle \nabla^{2}_{}$$\displaystyle {1 \over {\vert r\vert}}$ = 0      $\displaystyle \mbox{wenn $r \neq 0$}$ (2.32)

$\displaystyle \nabla$ x ($\displaystyle \vec{J}\,$ x $\displaystyle \vec{B}\,$) = $\displaystyle \vec{J}\,$($\displaystyle \nabla$ . B) + $\displaystyle \vec{J}\,$ x ($\displaystyle \nabla$ x $\displaystyle \vec{B}\,$) - $\displaystyle \nabla$($\displaystyle \vec{J}\,$ . $\displaystyle \vec{B}\,$) (2.33)


next up previous contents
Next: 2.5 Integralsätze Up: 2. Vektoranalysis, Feldtheorie Previous: 2.3 Gradient, Divergenz, Rotation,   Inhalt
Alexander Wagner
2000-04-14