Test

[math]\operatorname{grad}\,\varphi=\nabla\varphi=\frac{\partial\varphi}{\partial x}\vec{e}_x+\frac{\partial\varphi}{\partial y}\vec{e}_y+\frac{\partial\varphi}{\partial z}\vec{e}_z = \begin{pmatrix} \partial\varphi / \partial x \\ \partial\varphi / \partial y \\ \partial\varphi / \partial z \end{pmatrix}[/math]