%%time
import sys
sys.version
CPU times: user 0 ns, sys: 0 ns, total: 0 ns Wall time: 10.7 µs
$ y_{it} = \alpha + \beta d_{it} + f(x_{it} - 0.05) + d_{it} g(x_{it} - 0.05) + \varepsilon_{it} $
%%latex
\begin{align}
\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{align}