Exponential Integral

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exponential integral

[‚ek·spə′nen·chəl ′int·ə·grəl]
(mathematics)
The function defined to be the integral from x to ∞ of (e -t / t) dt for x positive.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Exponential Integral

 

a special function defined by the integral

This integral cannot be expressed in closed form through elementary functions. If x > 0, then the integral is understood in the sense of its principal value:

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Thus, in the empirical model, we test the relationship between export performances (EXPINT) on the variables described above (Chart 1).
EXPINT = f (SIZE, SIZESQ, FS, KINT, CGINT, DISTECH, ADVINT, RMIMP, AGE)
The OLS estimation is not appropriate when dealing with export performance behavior since it does not take into account the restriction the bound of the export performance, i.e., 0 [less than or equal to] EXPINT [less than or equal to] 1 where EXPINT is defined as export/total sales (Wagner, 2001).