Formula:2987

Digital Library of Mathematical Functions ID 6.12.E1

${\displaystyle{\displaystyle E_{1}\left(z\right)\sim\frac{e^{-z}}{z}\left(1-\frac{1!}{z}+\frac{2!}{z^{2}}-\frac{3!}{z^{3}}+\cdots\right),}}$

Constraint(s)

${\displaystyle{\displaystyle|\operatorname{ph}z|\leq\tfrac{3}{2}\pi-\delta(<\tfrac{3}{2}\pi)}}$
${\displaystyle{\displaystyle z\to\infty}}$
${\displaystyle{\displaystyle|\operatorname{ph}z|\leq\tfrac{3}{2}\pi-\delta(<\tfrac{3}{2}\pi)}}$

Symbols List

• ${\displaystyle{\displaystyle\sim}}$:
• ${\displaystyle{\displaystyle\pi}}$: the ratio of the circumference of a circle to its diameter
• ${\displaystyle{\displaystyle\mathrm{e}}}$: base of natural logarithm
• ${\displaystyle{\displaystyle E_{1}\left(\NVar{z}\right)}}$: exponential integral
• ${\displaystyle{\displaystyle!}}$:
• ${\displaystyle{\displaystyle\operatorname{ph}}}$: phase
• ${\displaystyle{\displaystyle z}}$: complex variable
 

Resources that cite this formula

No records found.