March 14th - Happy Pi Day everyone!!

[wolf_meister]

If someone has already started a Pi Day thread then please just delete this. (I did an SDMB search for this and the result was "the following words in your search were too short or too common - 'pi' and 'day' :D

Yes, March 14th or 3/14 is the unofficial annual celebration of everyone's favorite transcendental number.

As if that isn't intellectual enough for you, it is also the birthday of Albert Einstein.

[standingwave]

You know, Tau Day (http://tauday.com/#sec:the_circle_constant)... :)

[flatlined]

If someone has already started a Pi Day thread then please just delete this. (I did an SDMB search for this and the result was "the following words in your search were too short or too common - 'pi' and 'day' :D

Yes, March 14th or 3/14 is the unofficial annual celebration of everyone's favorite transcendental number.

As if that isn't intellectual enough for you, it is also the birthday of Albert Einstein.

You are totally my 42 :)

[EvilTOJ]

By coincidence I'm wearing this (http://shirt.woot.com/friends.aspx?k=17682) shirt today.

[installLSC]

The only problem with Pi Day this year is it's on a Monday, and we're on a Tuesday-Saturday schedule at work. We were going to have it tomorrow, but people then decided they want it on the 16th.

[wolf_meister]

And should any folks want to type the actual symbol π
hold down ALT and type 227 on the keypad and you'll get

π

Changing the font size and font type (Times New Roman looks pretty good) also helps.

[Rigamarole]

In 10 minutes and 265 milliseconds (in my timezone) it's going to be 3/14 1:59.265!!! This calls for celebration.

[Lorski]

Happy Birthday to me! :D

[Alka Seltzer]

Is this why it's Pie week at my local pub?

[Scuba_Ben]

I like pi. When come back bring digits of pi.

[Autolycus]

Pi Day? Grow up you guys. Stop being so irrational.

[Dragwyr]

I like pi. When come back bring digits of pi.

Ok. Here you go:

3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706 79...

My one useless skill is that I have memorized the first 100 digits of pi (π). Lets just say it was a long LONG drive back home from a Tennessee.

[Annie-Xmas]

Let's all gather round in a circle...

[johnpost]

Mmmmmm numerical pie!

[Hari Seldon]

If someone has already started a Pi Day thread then please just delete this. (I did an SDMB search for this and the result was "the following words in your search were too short or too common - 'pi' and 'day' :D

Yes, March 14th or 3/14 is the unofficial annual celebration of everyone's favorite transcendental number.

As if that isn't intellectual enough for you, it is also the birthday of Albert Einstein.

Not only that, it is my wedding anniversary! First thing I said to my wife of 47 years this morning was "Happy Einstein's birthday!"

[wolf_meister]

Hari Seldon - not only is it the date of your wedding anniversary, it's the birth date of a lot of famous people:

Les Brown - (his Band of Renown probably has other birth dates).
Hank Ketcham - Dennis the Menace Cartoonist
plus Quincy Jones, Michael Caine, and Billy Crystal

[penultima thule]

Unofficially we celebrate Pi Day on July 22nd (22/7)

[flatlined]

Big sighs here. I'm a geek. Its well known that I'm a geek. I laugh myself silly over shaggy dog jokes, I work 42 into casual conversation, when I'm on hold I'll often hand calculate Pi and will show how far I got as examples of long hold times "Look! 6 pages! SIX!!! I hate calling this company." I also NEVER cook food to share at work.

For the 3rd 3.14 in a row, I baked a pie and took it to work. I'll even say "Happy Pi Day" while offering it to my coworkers.

Nobody has ever gotten it :(

[Noel Prosequi]

Now see this is where you Americans get the month/day convention so wrong - the convention is day/month in much of the rest of the world. So pi day should be 31 April. I leave determining the rationality of that as an exercise for the reader.

[gregorio]

Damn! I missed steak and a bj day again!

Also, white underpants day.

I gotta get an app or something.

[thirdwarning]

Not only that, it is my wedding anniversary! First thing I said to my wife of 47 years this morning was "Happy Einstein's birthday!"

It's my wedding anniversary, too. Only thirty here, though. So, belatedly, happy pi day, happy Einstein's birthday, and happy anniversary to you and your lovely wife.

[RTFirefly]

Circle, I've got your number
digits so sweet and fine
circumf'rence over diameter
three point one four one five niiiine
three point one four one five niiiine

I think you can guess the tune. :)

[flatlined]

RTFirefly I'm not sure if I want to have your babies for that, or kill you for the mindworm.

Well done :)

[alindallas]

Damn you, Firefly! Now I'm off to YouTube to listen to "Jenny"!

[dhkendall]

My Facebook status on March 14 (and still is, as I rarely change it) was:

Yes, I like a happy, beautiful pi holiday.

I'll leave it without comment, as I know Dopers are smart enough to see what I just did there.

[AaronX]

Big sighs here. I'm a geek. Its well known that I'm a geek. I laugh myself silly over shaggy dog jokes, I work 42 into casual conversation, when I'm on hold I'll often hand calculate Pi and will show how far I got as examples of long hold times "Look! 6 pages! SIX!!! I hate calling this company." I also NEVER cook food to share at work.

For the 3rd 3.14 in a row, I baked a pie and took it to work. I'll even say "Happy Pi Day" while offering it to my coworkers.

Nobody has ever gotten it :(

Please, do tell how do you hand calculate pi? Is it by an infinite series of fractions?

[brewha]

My daughter is a pi baby. I was actually a little dissapointed when 1:59 AM passed, since I knew she wouldn't make it to 1:59PM. And 3.14.5:34 doesn't mean a whole lot.
Yes, she did get pie instead of cake for when she turned two last week!

[Electric Warrior]

Some friends had their daughter at exactly 1:59 AM on Monday morning. Now they're worried she might grow up to be a mathematician. ;)

[flatlined]

Please, do tell how do you hand calculate pi? Is it by an infinite series of fractions?

HURRAY!!! A geek question for me :D

Pi= circumference / diameter. It doesn't matter how large the circle is, the math works out the same always.

I've never used fractions for Pi, its always been long division. Plug in the numbers and start subtracting.

I'm kinda new...was this my first woosh? If not, I'd be thrilled to talk Pi with you...cause I don't understand how one would use fractions for Pi.

[flatlined]

Some friends had their daughter at exactly 1:59 AM on Monday morning. Now they're worried she might grow up to be a mathematician. ;)

I'm afraid that it might be even worse than that. She might grow up to be an engineer :eek:

[surrounded by literalists]

Next year, you are invited to the Community College where I work. A week before pi day we set up a jar for each science professor. Students, staff and faculty put money in the jar of the professor that they wanted to see get a pie in the face. Some shenanigans similar to episodes of 'Survivor' transpired (long story), but in the end, our psychology professor was pi-ed. Good times!

[Autolycus]

Well, Pi Day has come and gone. It was fun while it lasted, but now it is time to look forward to... Tau Day! While it does not have the same cool, hipster aura to it, it is clearly a superior day. In fact, one could even say it is perfect. To Tau Day!

http://tauday.com/

[AaronX]

HURRAY!!! A geek question for me :D

Pi= circumference / diameter. It doesn't matter how large the circle is, the math works out the same always.

I've never used fractions for Pi, its always been long division. Plug in the numbers and start subtracting.

I'm kinda new...was this my first woosh? If not, I'd be thrilled to talk Pi with you...cause I don't understand how one would use fractions for Pi.

I know, but you need accurate values for circumference and diameter. Do you just draw a large circle and measure them?

I did a maths class that mentioned a few ways to calculate pi. Looking at the Wikipedia page, there are several infinite series for pi, which you could use to calculate it by hand. The difficult part is when you get to smaller and smaller decimal places, which is why I was wondering how you could calculate it to 6 pages.

Oh, there are more formulae at http://mathworld.wolfram.com/PiFormulas.html

[flatlined]

I know, but you need accurate values for circumference and diameter. Do you just draw a large circle and measure them?

(snip) As a geek, all of my math stuff involves measureing Dinty Moore Stew cans. I couldn't draw a good circle to save my life. But, honestly...it doesn't matter how big the circle is, the math will work out.

I did a maths class that mentioned a few ways to calculate pi. Looking at the Wikipedia page, there are several infinite series for pi, which you could use to calculate it by hand. The difficult part is when you get to smaller and smaller decimal places, which is why I was wondering how you could calculate it to 6 pages.

(more snips)

the best thing about Pi is that its anyone can do the paper and pencil by hand. Lots of people done't understand that long division is just subtraction compounded so they are frightened to try.

Oh, there are more formulae at http://mathworld.wolfram.com/PiFormulas.html

I think that we need to keep this thread open...because you are trying to learn how irrational us geeks can be.

PS.. Pi is an irrational number

[NomadUK]

Well, Pi Day has come and gone.

Well, as someone noted earlier, for those of us whose dates aren't backward, Pi Day should actually be 31 April -- which maps conveniently to 1 May, which is May Day, so a twofer! Which makes Tau Day 62 August, or 1 October. Easily remembered!

Or maybe they should just be 3 January and 6 Feburary, if you're not into too many decimal places.

[AaronX]

I think that we need to keep this thread open...because you are trying to learn how irrational us geeks can be.

PS.. Pi is an irrational number

Er, if you're just measuring, you won't be able to get pi, unless you have infinite accuracy. Why? Irrational numbers can't be expressed as fractions. When you divide circumference by diameter, that's actually a fraction. Another thing: all fractions end up as decimals with repeated sequences, so you can't keep dividing for long :D

[Thudlow Boink]

Er, if you're just measuring, you won't be able to get pi, unless you have infinite accuracy. Why? Irrational numbers can't be expressed as fractions. When you divide circumference by diameter, that's actually a fraction.If the circumference or diameter itself is irrational, dividing the circumference by the diameter would give you an irrational number. But you're not going to be able to take a physical, real-world measurement and get an irrational number.


I find it interesting that, even though pi has been known as a special number for thousands of years, it's only since the 1700's that it's been called "pi" (i.e. that the symbol π has been used). And it was only proved to be irrational in 1761. (By contrast, the ancient Greeks knew that the square root of 2 is irrational.)

[flatlined]

Er, if you're just measuring, you won't be able to get pi, unless you have infinite accuracy. Why? Irrational numbers can't be expressed as fractions. When you divide circumference by diameter, that's actually a fraction. Another thing: all fractions end up as decimals with repeated sequences, so you can't keep dividing for long :D

You are right, of course. You can't get good numbers with a stew can and a ruler. I usually go wrong 4 or 5 digits into the call. When I check my numbers with a calculator, my results are correct according to the data. GIGO happens:)

I've never been good with fractions, so the first thing I do when dealing with them is convert them to decimals. I'm quite sure most of the Garbage In starts there.

I'm not trying to win a Nobel prize with my scribblings, its a something to do while ignoring the hold muzak. Some people draw flowers or fill in the letters. I do long division with paper and a number 2 pencil :D

[Histrion]

I only have π memorized out to the "2643" myself. Used to know it a little further.

AaronX - the limit of a series of rationals can be irrational. For instance, successive Fibonacci numbers have a ratio that converges to (1 + sqrt(5) ) / 2, a.k.a. φ, the so-called "golden ratio."

flatlined - I think the question's still sort of hanging as to what exactly it is you're dividing by what (using long division of decimals or fractions, either way) to calculate π. Are you actually drawing a big circle and dividing circumference by diameter? (If so, the two follow-up questions: are you using standard 8.5 x 11" or A4, and how are you measuring the circumference? I think that's why some readers here might be a bit perplexed.)

I actually spent some time a few weeks ago using the Pythagorean Theorem to work out how to approximate pi as a succession of perimeters of inscribed polygons in the unit circle, doubling the number of sides each time. Turns out that, as in iterative formula, it actually works out pretty nicely. Wouldn't really work as flatlined's method, because it involves taking square roots, but if you have a calculator it converges pretty quickly:

Let x_1 = sqrt(2) (the length of one side of the inscribed square). As a first approximation, π = 2x_1 ≈2.8284.

Then, iterate, starting with i = 2:
x_i = sqrt( 1 + 0.5x_(i-1) ) - sqrt( 1 - 0.5x_(i-1) ) ; π ≈ (2^i)x_i

You get:

x_1 ≈ 1.414213562 π ≈ 2x_1 ≈ 2.828427125
x_2 ≈ .7653668647 π ≈ 4x_2 ≈ 3.061467459
x_3 ≈ 0.3901806440 π ≈ 8x_3 ≈ 3.121445152
x_4 ≈ 0.1960342807 π ≈ 16x_4 ≈ 3.136548491

By the time you get to i = 10, your π value is accurate to the 5th decimal place. At that point the inscribed polygon has 2048 sides, each of length x_10 ≈ 0.003. You wind up gaining about one more digit of accuracy every two steps, until eventually your calculator's precision limits start introducing rounding errors.

In other words, flatlined, you're not the only one around here who does math when he's bored. I've been experimenting with the arithmetic of continued fractions lately, myself.

[surrounded by literalists]

And they say women are irrational (snicker!)

[flatlined]

And they say women are irrational (snicker!)

Big grins :D

Welcome to the board. I'd so love to have been involved with your college Pi day event. I'll bet that there were sliderule smackdowns involved. Yes, I do own a sliderule and I know how to use it. (sliderules are better than a ruler for smacking my clerk around, sliderules extend)

Histrion nice job. Now I'm going to be messing around with that. For the record, using my tape measure and a beer can, Pi is now proved to be 3.2. What this proves is:

1. I'm not using a good measuring tool.
2. I'm measureing the outside and not the real circumference.
3. I forgot what I should be saying here.
4. Beer makes me think I'm smarter than other people think I am :smack:

[Histrion]

Histrion nice job. Now I'm going to be messing around with that. For the record, using my tape measure and a beer can, Pi is now proved to be 3.2. What this proves is:

1. I'm not using a good measuring tool.
2. I'm measureing the outside and not the real circumference.
3. I forgot what I should be saying here.
4. Beer makes me think I'm smarter than other people think I am :smack:

5. When you went to measure the diameter, you didn't cross the exact center of the circle. That made your diameter too small, which led to a figure for π that was too big.

I have my dad's Post/Hemi Versalog from his college days. Beautiful thing.

I also have a plastic Pickett. And a similar model from thinkgeek.com, which is modeled after the Pickett and even includes the Pickett instructions, but is more cheaply made - the rules on one side don't line up well with the ones on the other, and the numbers rub off when you try to vaseline the center piece. :smack:

[Histrion]

And they say women are irrational (snicker!)

They mostly are.

*waits to see who jumps down my throat -- check the post title ;) *

[surrounded by literalists]

ahem...And just what is the gender of those involved in this gladitorial geek fight?

[Histrion]

ahem...And just what is the gender of those involved in this gladitorial geek fight?

Well, I'm male. Haven't looked at anyone else's bits.

Geez, I'm ornery tonight.

[surrounded by literalists]

nuff' said (nose in the air and hair toss followed by a forgive me grin).

[Histrion]

Oh, don't worry - I only say that women are mostly irrational as the conclusion of a syllogism whose first premise is that people are mostly irrational. :p

[flatlined]

IMO, the best part of this sort of communication is that people don't look at my boobs and think that I can't think. I'm not irrational, I'm transcendental :cool:

Surrounded...you have a PM.

going back to my beer can. well a different one, the last one had a hole in it. anyhow...now using a compas and a good ruler. Pi is 3.47

Beer is good. taling math while imbiding is not so good.

[AaronX]

You are right, of course. You can't get good numbers with a stew can and a ruler. I usually go wrong 4 or 5 digits into the call. When I check my numbers with a calculator, my results are correct according to the data. GIGO happens:)

I've never been good with fractions, so the first thing I do when dealing with them is convert them to decimals. I'm quite sure most of the Garbage In starts there.

I'm not trying to win a Nobel prize with my scribblings, its a something to do while ignoring the hold muzak. Some people draw flowers or fill in the letters. I do long division with paper and a number 2 pencil :D

As long as you know that :) Don't let me stop you doing something you like. I looked through my notes for that maths subject, but couldn't find any easy way to calculate pi by hand. If you're going to use a computer, Richardson extrapolation and Romberg integration are very useful though.

[NoCoolUserName]

4. Beer makes me think I'm smarter than other people think I am :smack:Here's how it works:

A herd of buffalo can only move as fast as the slowest buffalo. And when the herd is hunted, it’s the slowest and weakest ones at the back that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular killing of the weakest members.

In much the same way, the human brain can only operate as fast as the slowest brain cells. Now, as we know, excessive intake of alcohol kills brain cells. But naturally, it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making the brain a faster and more efficient machine.

And that, flatlined, is why you always feel smarter after a few beers.

[flatlined]

I'm so cracking up now. No beer involved, but laughing hard enough to have water coming out of my eyes. Is it ok if I steal that to use at work tomorrow?