$\sqrt{3x-1}+(1+x)^2$

测试脚注 ^[1]

$$\begin{array}

\nabla \times \vec{\mathbf{B}} -, \frac1c, \frac{\partial\vec{\mathbf{E}}}{\partial t} & = \frac{4\pi}{c}\vec{\mathbf{j}} \nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \

\nabla \times \vec{\mathbf{E}}, +, \frac1c, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \

\nabla \cdot \vec{\mathbf{B}} & = 0

\end{array}$$