14 DAY TRIAL // Yesterday was Pi Day, 3.14 celebrated by math nerds, and now Google, worldwide. Having been conspicuously missing from Google's ever-growing repertoire of special-event doodles for years now, Google has finally relented and unleashed its inner nerd, not that it tried to hide it too hard in the past.
And, perhaps to make up for all the years it skipped, Google went all out this time and showed off six common uses of the famous number. The Pi Day Google logo starts off with the formula everyone knows (?) for the area of a circle A = πr2, but goes on with some more advanced stuff. The two 'os' in Google are used to represent the sin(x) function over a 2π period.
The volume of a sphere (V = 4⁄3 πr3) is also depicted, as is the volume of a cylinder (V = πr2h). Of course, the circumference of a circle, C = 2πr, couldn't be left out. On the more esoteric side, there is Archimedes’ calculation of Pi, which is 223/71 < π < 22/7. Of course, any math nerd will tell you that this is more or less kindergarten stuff, but, for the average guy, it's as ‘rocket-sciencey’ as it gets. And it's nice to see the famous number get the kind of recognition it deserves.
And now for a little math/history lesson. π is defined as the ration between a circle's circumference and its diameter. It's an irrational number, so it goes on forever, but it is commonly shortened as 3.14, which is why the 14th of March is chosen to celebrate it.
It has fascinated mathematicians for thousands of years and the first approximation for the number dates back to the Egyptians and the pyramids. You can read all about this stuff on the trusty Wikipedia. Pi Day comes once a year, obviously, but there is a special event brewing, a once-in-a-lifetime Pi Day in 2015 when, on 3/14/15 at 9:26:53.589, pi will be approximated within 12 digits.