Product rule for divergence
= Product rule for divergence
For a scalar field $\phi$ and vector field $F$,
$$
\nabla\mathbin\cdot(\phi F)=\nabla\phi\mathbin\cdot F+\phi\nabla\mathbin\cdot F.
$$
= Product rule for divergence
For a scalar field $\phi$ and vector field $F$,
$$
\nabla\mathbin\cdot(\phi F)=\nabla\phi\mathbin\cdot F+\phi\nabla\mathbin\cdot F.
$$