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Now that you are so smart and you became a pi expert, what is the number 3.14159 with a scoop of ice cream called? ... And the answer is

Dreaming up "algorithms" (techie talk for "methods") to compute Pi has occupied the world's great minds for more than two millennia. Clearly these aren't guys you'd want to go on a long fishing trip with. The ancient Greeks used a simple method: You draw polygons, e.g., hexagons ... around a circle with a diameter of one ... one hexagon inside the circle, one out. Calculate the perimeter of the polygons (which is pretty straightforward), take an average, and you get a rough idea of Pi. Use polygons with more sides and your approximation of Pi gets closer and closer. The mathematician Archimedes got as far as 96 sides, calculating that Pi was between 3.1408 and 3.1428.

Today's mathematicians use far more sophisticated algorithms involving converging infinite series. A converging infinite series is a mathematical sequence that approaches (but never actually reaches) - a target number called a limit. Take for example, the limit of the series: 1 + 1/2 + 1/4 + 1/8 + ... it is 2. But it never actually reaches 2; it is forever approaching 2. It gets closer and closer; but it never quite gets there.

Regarding the above series, Kerry Russell disagrees and wrote to me saying that there is a limit but also the answer is 2. If you immediately take the equation to its logical conclusion, the answer is of course 1.999... But mathematically 1.999... = 2. Here is his proof:

Let’s assume x = 1.999...
Therefore 10 x = 19.999...
So 10 x - x = 19.999... - 1.999...
Thus 9 x = 18
And x = 2

Long ago it was realized that certain infinite series converge on fractions (same as reciprocals of Pi). For example, in 1671, the mathematician, Leibniz, discovered that the series 1 - 1/3 + 1/5 - 1/7 + ... converges on Pi/4. This may seem strange. I mean, what do fractions have to do with the circumference of a circle? But it does, it does indeed.

The discovery of ever more "efficient" infinite series, that is, series that converge on Pi faster for each term you add, coupled with the development of bigger and better computers, has made it possible to calculate Pi to thousands, millions, and now billions of decimal places.

Why compute to one billion digits? Who knows; it's crazy. As one learned treatise notes, "thirty-nine places of pi suffice for computing the circumference of a circle girdling the known universe with an error no greater than the radius of a hydrogen atom" ... The real reason, many feel, is that like Mt. Everest, "because it's there" ... somewhat immature. Thank G-d the rest of us have put such foolishness behind us, and undertake more worthwhile activities, like playing with a computer? more time with family?