Physics equations/Local anchors and styles

long arrows and centered equations
$$\begin{matrix}\overrightarrow{v}=\frac{\Delta \overrightarrow{s}}{\Delta t} =\frac{\overrightarrow{s}_{final}-\overrightarrow{s}_{initial}}{t_{final}-t_{initial}}\end{matrix}$$

Hidden passage

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links

 * 1) https://meta.wikimedia.org/wiki/Help:Displaying_a_formula
 * 2) https://en.wikipedia.org/wiki/Help:Wiki_markup