We ask users to provide proof(s), reference(s) to proof(s), or further clarification on the proof(s) in this space.
: integral : http://dlmf.nist.gov/1.4#iv
: sine function : http://dlmf.nist.gov/4.14#E1
: inverse tangent function : http://dlmf.nist.gov/4.23#SS2.p1
: the base of the natural logarithm : http://dlmf.nist.gov/4.2.E11
: ratio of a circle's circumference to its diameter : http://dlmf.nist.gov/5.19.E4
: differential : http://dlmf.nist.gov/1.4#iv
We ask users to provide relevant URL links in this space.