Sunday, March 14, 2010

Pi Day

Well, that's what I get for sleeping late (which I do occasionally)...Mike has beaten me to a blog post about today being "Pi Day" - the day set aside to honor the number representing the ratio of a circle's diameter to its circumference, which we represent (for no obvious reason) by the Greek letter pi:
π

Phonetically,
π is the Greek representation of "p" sound (the voiceless bilabial stop) in other languages. Like most Greek letters, however, it has been usurped by generations of mathematicians and engineers to represent various ratios, constants, variables, and unknowns, or just to make impressive-looking equations to make students sweat. For example:

Which represents something to do with the incompressible flow of Newtonian fluids. Why we would need a complicated equation to calculate the incompressibility of Sir Isaac's urine, I'll never know, but that's not important now. And it doesn't contain any π's.

Let's get back to
π.The ratio represented by π is what mathematicians call an irrational number - that is, one which cannot be represented as the result of dividing one number by another. It is also a transcendental number - that is, it is not algebraic (not a solution of a non-constant polynomial equation with rational coefficients).

I have no idea what I just wrote.

But let's forget all that complicated stuff for a minute and talk about the π ratio. Pi is usually represented by the simple number 3.14 (it's been calculated out to about 2.7 trillion places, but that's a little lengthy for most day-to-day uses you might have for a Greek letter representing the ratio of a circle's diameter to its circumference). 3.14 can, of course, also represent the date "March 14th" - thus, "Pi Day." It is also, by happy coincidence, the birthday of noted mathematician and scientist Albert Einstein, born in Ulm, Germany on March 14, 1879. Einstein was a noted consumer of Greek letters, which he used to construct amazing formulas comprehensible only to other deep thinkers with massive brains. Here is a photo of Albert Einstein wishing you well as you try to understand all this stuff:

Anyhow, enough about π. Let's talk about the larger concept of irrational numbers. The official definition of an irrational number has to do with its quality of indivisibility (as we noted above); however, the modern definition probably has to do more with Republican economic theories. Oh, no ... wait ... those would be imaginary numbers - mathematicians define an imaginary number as one which can be represented as "bi." This does not refer to a number that swings both ways, but to a number in which "b" is a non-zero real number, and i can be defined as i2 = -1.

Got that?

Actually, imaginary numbers today are better defined in terms of competing theories of government: to a Republican they represent the vast amounts of money the government will take in by cutting taxes paid by everyone but you; to a Democrat they represent the money that will be used to fund all the social programs they champion.

I think that's a clearer explanation than one that invokes things like the square root of negative 1, Greek letters, or similar weird stuff, don't you?

Well, all this started with the fact that today is Pi Day. If you're mathematically inclined, go out and raise a glass to π today. And if π isn't your favorite Greek letter, there are plenty of other Greek letters for you to honor, such as:

Rho, as in the famous Supreme Court decision of "ρ v. Wade;" or,

Delta, as in actress Δ Burke...

Or even Sigma, as in the famous Dr. Σ Freud...

Sorry about that.

So, now that I've Greek-lettered you to death, go out and enjoy a piece of pi.

Have a good day. More thoughts tomorrow.

Bilbo

2 comments:

Mike said...

"the voiceless bilabial stop"

We were just talking about that the other day over a beer. In other words nobody could understand what anybody was saying.

Wv: hunguiz - Yes I iz.

SusieQ said...

Gee, and all along I was thinking that today was "Pie" day.

I even went to the trouble of baking one with an "irrational number" of calories.