We ask users to provide proof(s), reference(s) to proof(s), or further clarification on the proof(s) in this space.
: ratio of a circle's circumference to its diameter : http://dlmf.nist.gov/5.19.E4
: the base of the natural logarithm : http://dlmf.nist.gov/4.2.E11
: Euler's constant : http://dlmf.nist.gov/5.2#E3
: Euler's gamma function : http://dlmf.nist.gov/5.2#E1
: product : http://drmf.wmflabs.org/wiki/Definition:prod
: real part : http://dlmf.nist.gov/1.9#E2
We ask users to provide relevant URL links in this space.