Metadata
bibkey: nist2026dlmfbesselkintegral
authors: NIST Digital Library of Mathematical Functions
year: 2026
title: Modified Bessel functions, integral representations
doi: 10.18434/T4J30S
url: https://dlmf.nist.gov/10.32.E9
claim: "DLMF 10.32.9 gives the hyperbolic integral representation of the modified Bessel function K."
strata_touched:
- D5/S3/Analytic/GammaGammaNBU/Result
- D5/S3/Analytic/GauntBesselTail/Result
license: citation-only
triage: anchor
Modified Bessel K as a hyperbolic integral
Verified locator
https://dlmf.nist.gov/10.32.E9
DOI: 10.18434/T4J30S.
Equation 10.32.9:
K_ν(z) = ∫_0^∞ exp(−z cosh t) cosh(νt) dt, |ph z| < ½π
For real and real the integral is real. In particular, .