Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Imaginary parts of GAMMA(1/2+I*y)

  1. Oct 14, 2009 #1

    Does anyone know of an explicit formula for the Real and Imaginary parts of GAMMA(1/2+I*y) as functions of y ?

    I know about

    |GAMMA(1/2+I*y)|^2 =Re(GAMMA(1/2+I*y))^2+Im(GAMMA(1/2+I*y))^2= Pi/cosh(Pi*y)

    but can't find anything about each of the Real and Imaginary terms individually. Checked just about every reference book that exists, and tried to derive something myself with no luck.

    Thanks to anyone who can point me to a reference. You'd think that something like that must be known.
  2. jcsd
  3. Oct 15, 2009 #2
    Re: GAMMA(1/2+I*y)

    Perhaps not what you wanted...
    Real part
    [tex]\int _{0}^{\infty }\!{{\rm e}^{-t}}\sqrt {t}\cos \left( y\ln \left( t
    \right) \right) {dt}[/tex]
    Imaginary part
    [tex]\int _{0}^{\infty }\!{{\rm e}^{-t}}\sqrt {t}\sin \left( y\ln \left( t
    \right) \right) {dt}[/tex]
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook