Consider $\displaystyle \mbox{div}\,\left(\frac{y\vec i - x\vec j}{(x^2 + y^2)^{2}}\right)$.

(a) Is this a vector or a scalar? ? vector scalar

(b) Calculate it:
$\mbox{div}\,\left(\frac{y\vec i - x\vec j}{(x^2 + y^2)^{2}}\right) =$ + =