# Exponential integral Ei(x) (chart) Calculator

## Calculates a table of the exponential integral Ei(x) and draws the chart.

 $Ei(x)=-{\large\int_{\small -x}^{\hspace{25}\small\infty}\frac{\large e^{-t}}{\large t}}dt$
 initial value x [ increment repetition ]
 $\normal Exponential\ integral\ Ei(x)\\[10](1)\ Ei(x)=-{\large\int_{\small -x}^{\hspace{25}\small\infty}\frac{\large e^{-t}}{\large t}}dt\\(2)\ Ei(x)=\gamma+ln(x)+{\large\sum_{k=1}^{\infty}\frac{x^k}{kk!}} \hspace{20} x>0\\$
Exponential integral Ei(x) (chart)
 [1-4] /4 Disp-Num5103050100200
[1]  2016/10/10 07:43   Male / 50 years old level / An engineer / Very /
Purpose of use
Instructor for first year petroleum technicians.
Comment/Request
Thanks!!
[2]  2014/05/26 01:09   Male / 60 years old level or over / A teacher / A researcher / Very /
Purpose of use
needed to know the value of Ei(x) with x=-1/sqrt(2)
[3]  2009/10/01 10:07   Male / 30 level / A university student / Very /
Comment/Request
I like it.
[4]  2009/08/23 00:21   Male / 30 level / Others / Very /
Purpose of use
To check the validity of my implementation of NR routines in freepascal.
Comment/Request
Great site !

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