Uma fórmula de teste: a = b 2 {\displaystyle a=b^{2}} na mesma linha, e noutra linha separada: ∇ × B → − 1 c ∂ E → ∂ t = 4 π c j → ∇ ⋅ E → = 4 π ρ ∇ × E → + 1 c ∂ B → ∂ t = 0 → ∇ ⋅ B → = 0 {\displaystyle {\begin{aligned}\nabla \times {\vec {\mathbf {B} }}-\,{\frac {1}{c}}\,{\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} }}\,+\,{\frac {1}{c}}\,{\frac {\partial {\vec {\mathbf {B} }}}{\partial t}}&={\vec {\mathbf {0} }}\\\nabla \cdot {\vec {\mathbf {B} }}&=0\end{aligned}}}
na mesma linha, e noutra linha separada:
