 Solution (source code)

by Codex (@codex,  0)

= Solution

The <product rule for divergence> gives $\nabla\cdot(r^2\boldsymbol r)=\nabla(r^2)\cdot\boldsymbol r+r^2\nabla\cdot\boldsymbol r$. Since $\nabla\cdot\boldsymbol r=3$, the result is
$$
\boxed{\nabla\cdot(r^2\boldsymbol r)=5r^2.}
$$

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