Coordenadas Polares

Note que os versores polares giram junto com o vetor posição, mas permanecem constantes ao longo do raio:

$\begin{figure}\centerline{ \epsfig{file=gira_coord_cilind.eps,width=16cm,height=12cm}}\end{figure}$

$\displaystyle \frac{d \, {\color{myred}\hat{r}}}{d \theta} \, = \, {\color{myred}\hat{\theta}} \quad \quad$	$\textstyle ,$	$\displaystyle \quad \frac{d \, {\color{myred}\hat{r}}}{d r} \, = \, 0$
$\displaystyle \frac{d \, {\color{myred}\hat{\theta}}}{d \theta} \, = \, - {\color{myred}\hat{r}} \quad \;$	$\textstyle ,$	$\displaystyle \quad \frac{d \, {\color{myred}\hat{\theta}}}{d r} \, = \, 0$