deletions | additions       diff --git a/3.tex b/3.tex  index d72380b..9815b60 100644  --- a/3.tex  +++ b/3.tex 
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S = \frac{100}{1 + \left(\frac{d}{e\sqrt{\alpha}}\right)^4}  \end{equation}  For a city the size of Barcelona, for example, with $\alpha = 0.478$: \approx 0.5$: