English

Evaluation of the non-elementary integral $\int e^{\lambda x^\alpha} dx, \alpha\ge2$, and other related integrals

Classical Analysis and ODEs 2018-07-03 v2

Abstract

A formula for the non-elementary integral eλxαdx\int e^{\lambda x^\alpha} dx where α\alpha is real and greater or equal two, is obtained in terms of the confluent hypergeometric function 1F1_1F_1. This result is verified by directly evaluating the area under the Gaussian Bell curve, corresponding to α=2\alpha = 2, using the asymptotic expression for the confluent hypergeometric function and the Fundamental Theorem of Calculus (FTC). Two different but equivalent expressions, one in terms of the confluent hypergeometric function 1F1_1F_1 and another one in terms of the hypergeometric function 1F2_1F_2, are obtained for each of these integrals, cosh(λxα)dx\int \cosh(\lambda x^\alpha)dx, sinh(λxα)dx\int \sinh(\lambda x^\alpha)dx, cos(λxα)dx\int \cos(\lambda x^\alpha)dx and sin(λxα)dx\int \sin(\lambda x^\alpha)dx, λC,α2\lambda\in \mathbb{C}, \alpha\ge2. And the hypergeometric function 1F2_1F_2 is expressed in terms of the confluent hypergeometric function 1F1_1F_1. Some of the applications of the non-elementary integral eλxαdx,α2\int e^{\lambda x^\alpha}dx,\alpha\ge2 such as the Gaussian distribution and the Maxwell-Bortsman distribution are given.

Keywords

Cite

@article{arxiv.1702.08438,
  title  = {Evaluation of the non-elementary integral $\int e^{\lambda x^\alpha} dx, \alpha\ge2$, and other related integrals},
  author = {Victor Nijimbere},
  journal= {arXiv preprint arXiv:1702.08438},
  year   = {2018}
}

Comments

15 pages, 1 figure

R2 v1 2026-06-22T18:29:48.648Z