Change of Variables & the Jacobian · Easy problem

Use spherical coordinates, with volume element $dV = \rho^2\sin\phi\,d\rho\,d\phi\,d\theta$, to find the volume of the solid $0 \le \rho \le 3$, $0 \le \phi \le \dfrac{\pi}{2}$, $0 \le \theta \le 2\pi$.