19.3. Infinite products Using the integral dt t et sin2 t 2 = 1 4 log 2...

19.3. Infinite products Using the integral dt t

e−βt sin2 αt 2

= 1 4

log

α2 +β2

β2 , and the identity satisfied by the functions

(α)(β)

(α +γ )(β −γ )

=

∞

k=0

1+ γ

α +k

1− γ

β +k

, to derive the expression of Fmin(θ) of the Sinh–Gordon model.