deletions | additions       diff --git a/4b2.tex b/4b2.tex  index 826c3fc..b887888 100644  --- a/4b2.tex  +++ b/4b2.tex 
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This holds true since:  \begin{equation}  \begin{cases}  i \leq n \iff &\iff&  i + 1 \leq n + 1\\ res = (i - 1)! \iff &\iff&  res * i = i! \end{cases}  \end{equation}