Recall that for a thin current-carrying loop we have \begin{eqnarray*} \BB(\rr) = {\mu_0\over 4\pi} \int {\II(\rrp)\times(\rr-\rrp)\,ds'\over|\rr-\rrp|^3} = - {\mu_0 I\over 4\pi} \int {(\rr-\rrp)\times d\rrp\over|\rr-\rrp|^3} \end{eqnarray*} Find an expression for the magnetic field for a spinning circular ring with radius $R$, charge $Q$, and period $T$. The expression should be valid everywhere in space and simplified enough that it could be evaluated by a computer algebra programs such as Mathematica or Maple.