π day is 3/14. March 14th last year was called super π day: 3/14/15. Years ago, as a student of electrical engineering, I memorized π this far out: 3.14159. So isn't today better called super π day? I mean, 3.1416 is closer to the value of π than 3.1415. Am I right? Of course I am.
The decimal expansion is non-terminating. But that is not what makes it an irrational number. What makes it irrational is that it cannot be expressed as a fraction the numerator and denominator of which are integers. Compare 1/3. Its decimal expansion is also non-terminating: .3333333 . . . . But it is a rational number because it can be expressed as a fraction the numerator and denominator of which are integers (whole numbers).
An irrational (rational) number is so-called because it cannot (can) be expressed as a ratio of two integers. Thus any puzzlement as to how a number, as opposed to a person, could be rational or irrational calls for therapeutic dissolution, not solution (he said with a sidelong glance in the direction of Wittgenstein).
Finally a quick question about infinity. The decimal expansion of π is non-terminating. It thus continues infinitely. The number of digits is infinite. Potentially or actually? (See Infinity category for some discussion of the difference.) I wonder: can the definiteness of π -- its being the ratio of diameter to circumference in a circle -- be taken to show that the number of digits in the decimal expansion is actually infinite?
I'm just asking.
Many people don't understand that certain words and phrases are terms of art, technical terms, whose meanings are, or are determined by, their uses in specialized contexts. I once foolishly allowed myself to be suckered into a conversation with an old man. I had occasion to bring up imaginary (complex) numbers in support of some point I was making. He snorted derisively, "How can a number be imaginary?!" The same old fool -- and I was a fool too for talking to him twice -- once balked incredulously at the imago dei. "You mean to tell me that God has an intestinal tract!"
Now go ye forth and celebrate π day in some appropriate and inoffensive way. Eat some pie. Calculate the area of some circle. A = πr2.
Dream about π in the sky. Mock a leftist for wanting π in the future. 'The philosophers have variously interpreted π; the point is to change it!'
But don't shout down any speaker or throw π in his face. That's what 'liberals' and leftists do, and you are a morally decent person who believes in free speech and open debate.
As a sort of 'make-up' for missing Saturday night's oldies show, here is Queen Jane Approximately.
Which Dylan song features the line "infinity goes up on trial"?
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