e (mathematical constant)
= e
{disambiguate=mathematical constant}
{c}
{title2=$e$}
{wiki}
= Euler's number
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{synonym}
<Euler's number> is the value $\exp(1)=\sum_{n=0}^{\infty}1/n!$ of the <exponential function>, approximately $2.71828$. It is the base of the <natural logarithm>. Its factorial-series tail gives an elementary proof of the <irrationality of e>. The <compounding limit for e> shows how the same constant arises from repeated small multiplications.