### Instruction: Convert the point $(\rho,\theta,\phi) = \left( 4, \frac{5 \pi}{3}, \frac{\pi}{2} \right)$ in spherical coordinates to rectangular coordinates.### Response: To convert from spherical to rectangular coordinates, I need to use the following formulas:

\[x = \rho \sin \phi \cos \theta\]
\[y = \rho \sin \phi \sin \theta\]
\[z = \rho \cos \phi\]