Publications Meetings The Profession Membership Programs Math Samplings Policy & Advocacy In the News About the AMS

Remote Access
Green Open Access
Mathematics of Computation
Mathematics of Computation
ISSN 1088-6842(online) ISSN 0025-5718(print)


Chebyshev approximations for the exponential integral $ {\rm Ei}(x)$

Authors: W. J. Cody and Henry C. Thacher
Journal: Math. Comp. 23 (1969), 289-303
MSC: Primary 65.25
MathSciNet review: 0242349
Full-text PDF Free Access

Abstract | References | Similar Articles | Additional Information

Abstract: The computation of the exponential integral $ Ei(x)$, $ x > 0$, using rational Chebyshev approximations is discussed. The necessary approximations are presented in well-conditioned forms for the intervals $ (0,6]$, $ [6,12]$, $ [12,24]$ and $ [24,\infty )$. Maximal relative errors are as low as from $ 8 \times {10^{ - 19}}to2 \times {10^{ - 21}}$. In addition, the value of the zero of $ Ei(x)$ is presented to 30 decimal places.

References [Enhancements On Off] (What's this?)

Similar Articles

Retrieve articles in Mathematics of Computation with MSC: 65.25

Retrieve articles in all journals with MSC: 65.25

Additional Information

PII: S 0025-5718(1969)0242349-2
Article copyright: © Copyright 1969 American Mathematical Society

Comments: Email Webmaster

© Copyright , American Mathematical Society
Contact Us · Sitemap · Privacy Statement

Connect with us Facebook Twitter Google+ LinkedIn Instagram RSS feeds Blogs YouTube Podcasts Wikipedia