 evalVF - Maple Help

Student[VectorCalculus]

 evalVF
 evaluate a vector field at a point Calling Sequence evalVF(F, v) Parameters

 F - vector field or Vector-valued procedure; specify the components of the vector field v - free or position Vector; specify the point at which to evaluate the vector field Description

 • The evalVF(F, v) calling sequence evaluates the vector field F at the point v.  The parameters, F and v, must have the same dimension, but do not need to be defined in the same coordinate system.
 • The vector field parameter, F, can also be specified as a Vector-valued procedure, in which case this procedure is evaluated at the coordinates of the Vector v. Examples

 > $\mathrm{with}\left(\mathrm{Student}\left[\mathrm{VectorCalculus}\right]\right):$
 > $\mathrm{SetCoordinates}\left(\mathrm{polar}\left[r,\mathrm{\theta }\right]\right)$
 ${{\mathrm{polar}}}_{{r}{,}{\mathrm{\theta }}}$ (1)
 > $F≔\mathrm{VectorField}\left(⟨{r}^{2}\mathrm{\theta },-\mathrm{\theta }⟩\right)$
 ${F}{≔}\left({{r}}^{{2}}{}{\mathrm{\theta }}\right){\stackrel{{_}}{{e}}}_{{r}}{+}\left({-}{\mathrm{\theta }}\right){\stackrel{{_}}{{e}}}_{{\mathrm{θ}}}$ (2)
 > $\mathrm{simplify}\left(\mathrm{evalVF}\left(F,⟨1,\frac{\mathrm{\pi }}{2}⟩\right)\right)$
 $\left[\begin{array}{c}\frac{{\mathrm{\pi }}}{{2}}\\ {-}\frac{{\mathrm{\pi }}}{{2}}\end{array}\right]$ (3)
 > $\mathrm{evalVF}\left(\left(a,b\right)↦⟨{a}^{2},{b}^{2}⟩,\mathrm{Vector}\left(\left[0,1\right],\mathrm{attributes}=\left[\mathrm{coordinates}=\mathrm{cartesian}\right]\right)\right)$
 $\left[\begin{array}{c}{1}\\ \frac{{{\mathrm{\pi }}}^{{2}}}{{4}}\end{array}\right]$ (4)