Integrating e^x /x using Laurent series

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SUMMARY

The integral of the function \(\int \frac{e^x}{x}dx\) is expressed as the exponential integral function, \(\text{Ei}(x)\). While one participant suggested using a Laurent series for term-by-term integration, they also noted the limitations of integration by parts due to the increasing complexity of the expression. The discussion highlights that traditional methods may not yield a straightforward solution, and references to Abramowitz & Stegun's book provide a valuable resource for series expansion techniques related to this integral.

PREREQUISITES
  • Understanding of exponential functions and integrals
  • Familiarity with Laurent series and their applications
  • Knowledge of integration techniques, particularly integration by parts
  • Basic familiarity with the exponential integral function, \(\text{Ei}(x)\)
NEXT STEPS
  • Study the properties and applications of the exponential integral function, \(\text{Ei}(x)\)
  • Learn about Laurent series and their use in complex analysis
  • Explore advanced integration techniques, including integration by parts and ILATE method
  • Consult Abramowitz & Stegun's "Handbook of Mathematical Functions" for series expansions
USEFUL FOR

Mathematicians, students studying calculus, and anyone interested in advanced integration techniques and series expansions.

pivoxa15
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How does one integrate [tex]\int_{}^{} \frac{e^x}{x}dx[/tex]

I could expand it using a Laurent series and than integrating term by term but are there more elementary methods?
 
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courtrigrad said:
why can't you just use integration by parts twice? [tex]\int e^{x}\frac{1}{x} dx[/tex], [tex]u = e^{x}, du = e^{x}dx, dv = \frac{1}{x}, v = \ln x[/tex]
This just keeps expanding. Using ILATE, the algebraic part should be u, but this just keeping increasing in the power on the bottom. I don't think it's a good candidate for parts.

Edit: I'm not sure what happened to that post. Disregard I guess.
 
Since

[tex]\int \frac{e^{x}}{x} \ dx =\mbox{Ei}\left(x)[/tex]

you can search Abramowitz & Stegun's book on series expansion for this function.

Daniel.
 

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