If v = x²zi + 2y³z²j + xyz²k find div v.
Partially differentiating the first component of v w.r.t. x we find
{\frac{\partial v_{x}}{\partial x}}=2x zSimilarly,
{\frac{\partial v_{y}}{\partial y}}=6y^{2}z^{2} and {\frac{\partial v_{z}}{\partial z}}=2x y z
Adding these results we find
\mathrm{div}\,\mathbf{v}=\nabla\cdot\mathbf{v}=2x z+6y^{2}z^{2}+2x y z