WeBWorK Standalone Renderer

Let $\vec{F}$ be the vector field in the figure. At a distance $r$ from the z-axis, $\vec{F}$ has magnitude $3 r$ .

(a) Find a formula for $\vec{F}$ .
$\vec{F}$ =

(b) Find $\mathrm{curl}(\vec{F})$ using the coordinate definition and relate your answer to circulation density.
$\mathrm{curl}( \vec{F} )$ =

You can earn partial credit on this problem.