## Slicing the pi…

Calculating the value of pi, the mathematical constant that is the ratio of a circle’s circumference to its diameter, is a Sisyphean task– it goes on forever. And from a practical point of view, it’s silly: resolution to just 39 digits is enough to calculate the circumference of a circle the size of the observable universe with an error no larger than the radius of a hydrogen atom.

Still, the quest continues. As **i09 reports**…

A pair of pi enthusiasts have calculated the largest chunk of the mathematical constant yet, reaching just over 10 trillion digits. Alexander Yee and Shigeru Kondo, respectively a computer scientist in the US and a systems engineer in Japan, fought hard-drive failures and narrowly missed widespread technical disruptions due to the Japan earthquake to break their previous Guinness world record of 5 trillion digits…

Read the whole story (well, the story-to-date) at “**Epic pi quest sets 10 trillion digit record**.”

**As we remember that “pi aren’t square, pie are round,”** we might recall that it was on this date in 1675 that Gottfried Wilhelm von Leibniz first used the “long S” as the symbol of the integral in calculus. Leibnitz’s first such uses were in in private manuscripts; the first public appearance was in his paper “De Geometria,” published in (the appropriately-titled) *Acta Eruditorum* in June 1686.

The integral of a function of x over the interval [a,b] (*source*)