# Exponential integral Ei(x) Calculator

## Calculates the exponential integral Ei(x).

 $Ei(x)=-{\large\int_{\small -x}^{\hspace{25}\small\infty}\frac{\large e^{-t}}{\large t}}dt$
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 $\normal Exponential\ integral\ Ei(x)\\[10](1)\ Ei(x)=-{\large\int_{\small -x}^{\hspace{25}\small\infty}\frac{\large e^{-t}}{\large t}}dt\\(2)\ Ei(x)=\gamma+ln(x)+{\large\sum_{k=1}^{\infty}\frac{x^k}{kk!}} \hspace{20} x>0\\$
Exponential integral Ei(x)
 [1-10] /31 Disp-Num5103050100200
[1]  2018/11/29 12:00   Male / 30 years old level / High-school/ University/ Grad student / Very /
Purpose of use
Single-Phase Fluid Flow in Reservoirs
[2]  2017/11/21 04:11   Male / 20 years old level / An engineer / Very /
Purpose of use
thanks
[3]  2017/11/14 02:28   Male / 60 years old level or over / A retired people / Very /
Purpose of use
Solution to equation relating to climate change
[4]  2016/09/12 23:10   Male / 20 years old level / High-school/ University/ Grad student / Very /
Purpose of use
to find solution for flow through fractures
Comment/Request
useful
[5]  2015/12/10 04:29   Male / 60 years old level or over / An engineer / Very /
Purpose of use
Darcy's Eq for early time gas well drawdown
Comment/Request
Very handy
[6]  2015/04/17 19:01   Male / 30 years old level / An engineer / A little /
Purpose of use
Validate software result
[7]  2015/01/11 15:15   Male / Under 20 years old / High-school/ University/ Grad student / Useful /
Purpose of use
Solving a double integral question which has an ExpInt as the inner integral
[8]  2014/12/19 20:56   Male / 50 years old level / An engineer / Very /
Purpose of use
Interference Test Calculations
[9]  2014/08/19 23:58   Male / 40 years old level / A teacher / A researcher / Very /
Purpose of use
compare approximate function (my own) to tabulated data.
[10]  2014/05/29 18:40   Male / 60 years old level or over / A teacher / A researcher / Very /
Purpose of use
research work in high energy physics

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