Result: Approximate values of the integral logarithm and the exponential integral function.

Title:
Approximate values of the integral logarithm and the exponential integral function.
Authors:
Krastev, Roumen K.
Publisher Information:
Bulgarian Academy of Sciences, National Committee for Mathematics, Sofia
Subject Terms:
Computation of special functions and constants, construction of tables, Other functions defined by series and integrals, Numerical approximation and evaluation of special functions, exponential integral function, integral logarithm
Document Type:
Academic journal Article
File Description:
application/xml
Access URL:
https://zbmath.org/2063902
Accession Number:
edsair.c2b0b933574d..1cd686d9182d12883488db108ba4b5af
Database:
OpenAIRE

Further Information

Summary: The author obtains approximate values of the exponential integral function and the integral logarithm: \(\text{li} (x)=\ln (r-px-qx^2)\), where \(r=1.0013\), \(p=0.259\), \(q=0.741\). The solutions are valid in particular intervals with errors less than \(1\%\). The formulae are applicable for instance to the analytical description (finding of parameters) of physical processes determined by these integrals.