1) Except for a very long current carrying wire, the magnetic flux density B surrounds the wire and is inversely proportional to the distance from the wire axis. Let this long wire coincide with the z-axis of the cylindrical coordinate system. According to the problem: B = @ *. Find the divergence of this vector field (r, 9, z) in cylindrical coordinates.

1) Except for a very long current carrying wire, the magnetic flux density B surrounds the wire and is inversely proportional to the distance from the wire axis. Let this long wire coincide with the z-axis of the cylindrical coordinate system. According to the problem: B = @ *. Find the divergence of this vector field (r, 9, z) in cylindrical coordinates.