# Divergence of B, circular current loop

## Homework Statement

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∇ * B = 0 and ∇ X B = Mu * J. This is proved to hold not only for infinite wires but for magnetostatics in general.

Closed wire loop with constant current is certainly a magnetostatics example.

Magnetic field on z axis above loop around origin is: B = (Mu* I * R^2)/(2 * (R^2 + z^2)^(3/2)) in z hat direction

## Homework Equations

Partial derivative with respect to z gives a non zero answer. Divergence is not zero. I am missing something obvious but fail to see what.

TeethWhitener