Category:Characterization of Exponential Integral Function

This category contains pages concerning Characterization of Exponential Integral Function:

Formulation $1$

Let $\Ei: \R_{>0} \to \R$ denote the exponential integral function:

$\map \Ei x = \ds \int_{t \mathop = x}^{t \mathop \to +\infty} \frac {e^{-t} } t \rd t$

Then:

$\ds \map \Ei x = -\gamma - \ln x + \int_0^x \frac {1 - e^{-u} } u \rd u$

Formulation $2$

Characterization of Exponential Integral Function/Formulation 2