Exponential Integral(redirected from Expint)
exponential integral[‚ek·spə′nen·chəl ′int·ə·grəl]
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 It might be outdated or ideologically biased.
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.