The king of numbers
It is undoubtedly the most famous constant in all of mathematics after 0 or 1. The number π, whose history spans several millennia and continues to be written to this day, exerts a manifest fascination. Is it because of its omnipresence in geometry and its link with this perfect shape that is the circle? Or because the infinite sequence of its decimals seems totally random? Or yet because of the abyss that separates the simplicity of its definition from the difficulty one has in establishing its properties? What is certain is that π continues to give work to scientists and to intrigue us.
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It’s quite a story…
The constant π is everywhere in mathematics. It is undoubtedly the best-known irrational number—and even the best-known transcendental number. How is it defined geometrically, and why does it appear in every branch of mathematics?
Pi, a number beyond reason
Since π is defined as the ratio of a circle's circumference to its diameter, it would be convenient if it were rational—that is, the quotient of two integers. Unfortunately, it is not! Worse still, some might say, it is even transcendental…
It's everywhere!
π turns up almost everywhere, sometimes even in the most fanciful fields. In mathematics, of course, we encounter it in geometry, analysis and number theory… As a result of this omnipresence, it appears throughout the other sciences too!
By law, π = 3.2
Well, almost… because the bill did not pass!
Record for memorizing digits of pi: 70,000 | Tangente
Pi Day is celebrated every year on March 14: in the American date format, this is written 3/14.
An astonishing coincidence!
The Borwein brothers, Jonathan (1951–2016) and David (1953–2020), worked extensively on—and published widely about—the number π.
The endless quest for decimal places
Visitors to the Palais de la découverte cannot help being fascinated by the sequence of π's decimal digits in the rotunda devoted to it. The digits seem to occur in no apparent order. Yet they are the result of a calculation!