Wolfram MathWorld
Look up mathematical definitions, formulas, and references.
What it is
Look up mathematical definitions, formulas, and references. The Pi entry collects definitions, representations, and further references.
Why it is selected
Terms, formulas, and citations in one entry make a useful starting reference.
Who it suits and when to use it
Useful for maths learners and editors; follow primary references for formal claims.
Usage note
The entry was read; linked calculators and every identity were not independently tested.
