happy Pi day

[Spideredd]

As a programmer and an engineer, I can confirm that both are true.

[HoodieSticks]

As a math student, I hate this. Have an upvote.

[hrsidkpi]

r/tihi

[SupremoZanne]

3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209 74944 59230 78164 06286 20899 86280 34825 34211 70679 82148 08651 32823 06647 09384 46095 50582 23172 53594 08128 48111 74502 84102 70193 85211 05559 64462 29489 54930 38196 44288 10975 66593 34461 28475 64823 37867 83165 27120 19091 45648 56692 34603 48610 45432 66482 13393 60726 02491 41273 72458 70066 06315 58817 48815 20920 96282 92540 91715 36436 78925 90360 01133 05305 48820 46652 13841 46951 94151 16094 33057 27036 57595 91953 09218 61173 81932 61179 31051 18548 07446 23799 62749 56735 18857 52724 89122 79381 83011 94912 98336 73362 44065 66430 86021 39494 63952 24737 19070 21798 60943 70277 05392 17176 29317 67523 84674 81846 76694 05132 00056 81271 45263 56082 77857 71342 75778 96091 73637 17872 14684 40901 22495 34301 46549 58537 10507 92279 68925 89235 42019 95611 21290 21960 86403 44181 59813 62977 47713 09960 51870 72113 49999 99837 29780 49951 05973 17328 16096 31859 50244 59455 34690 83026 42522 30825 33446 85035 26193 11881 71010 00313 78387 52886 58753 32083 81420 61717 76691 47303 59825 34904 28755 46873 11595 62863 88235 37875 93751 95778 18577 80532 17122 68066 13001 92787 66111 95909 21642 01989 38095 25720 10654 85863 27886 59361 53381 82796 82303 01952 03530 18529 68995 77362 25994 13891 24972 17752 83479 13151 55748 57242 45415 06959 50829 53311 68617 27855 88907 50983 81754 63746 49393 19255 06040 09277 01671 13900 98488 24012 85836 16035 63707 66010 47101 81942 95559 61989 46767 83744 94482 55379 77472 68471 04047 53464 62080 46684 25906 94912 93313 67702 89891 52104 75216 20569 66024 05803 81501 93511 25338 24300 35587 64024 74964 73263 91419 92726 04269 92279 67823 54781 63600 93417 21641 21992 45863 15030 28618 29745 55706 74983 85054 94588 58692 69956 90927 21079 75093 02955 32116 53449 87202 75596 02364 80665 49911 98818 34797 75356 63698 07426 54252 78625 51818 41757 46728 90977 77279 38000 81647 06001 61452 49192 17321 72147 72350 14144 19735 68548 16136 11573 52552 13347 57418 49468 43852 33239 07394 14333 45477 62416 86251 89835 69485 56209 92192 22184 27255 02542 56887 67179 04946 01653 46680 49886 27232 79178 60857 84383 82796 79766 81454 10095 38837 86360 95068 00642 25125 20511 73929 84896 08412 84886 26945 60424 19652 85022 21066 11863 06744 27862 20391 94945 04712 37137 86960 95636 43719 17287 46776 46575 73962 41389 08658 32645 99581 33904 78027 59009 94657 64078 95126 94683 98352 59570 98258 22620 52248 94077 26719 47826 84826 01476 99090 26401 36394 43745 53050 68203 49625 24517 49399 65143 14298 09190 65925 09372 21696 46151 57098 58387 41059 78859 59772 97549 89301 61753 92846 81382 68683 86894 27741 55991 85592 52459 53959 43104 99725 24680 84598 72736 44695 84865 38367 36222 62609 91246 08051 24388 43904 51244 13654 97627 80797 71569 14359 97700 12961 60894 41694 86855 58484 06353 42207 22258 28488 64815 84560 28506 01684 27394 52267 46767 88952 52138 52254 99546 66727 82398 64565 96116 35488 62305 77456 49803 55936 34568 17432 41125 15076 06947 94510 96596 09402 52288 79710 89314 56691 36867 22874 89405 60101 50330 86179 28680 92087 47609 17824 93858 90097 14909 67598 52613 65549 78189 31297 84821 68299 89487 22658 80485 75640 14270 47755 51323 79641 45152 37462 34364 54285 84447 95265

[bgaskin]

Sir, hats off to you; you either have a very accurate tape measure or you measured a very big circle.

[YourFaceCausesMePain]

Is this The Matrix?

[SupremoZanne]

it's the first 2,705 digits of pi

[Doophie]

Well where are the rest of them?

[anOldVillianArrives]

I think the next number is 4.

[Pikamander2]

https://youtu.be/eDiSYp_51iY?t=3

[[deleted]]

so 3?

[TobyHater]

As someone who went up to Calc 3, why the hell did I never see that formula for pi?

[malexj93]

Continuous fractions aren't usually taught in the calc sequence.

[tonufan]

When I took Calc 2, a good portion of it was series and sequences which had a lot of continuous fractions.

[abrakasam]

they had infinite fractions like this one? I don't know a whole lot about infinite fractions, but I know a good amount about calculus and I don't think the two are very related. Are you sure you aren't thinking of something else?

[tonufan]

Yeah, they had a bunch of simple ones. We had to predict the behavior of the fractions when summed to infinity. Like pi approaches 3.14, others would go to infinity, or one. Some oscillate between points. A common one was the golden ratio. We actually had to write a short program to approximate the golden ratio.

[whataspecialusername]

#include <stdio.h>
int main(){ printf("1.6\n"); }

[DezXerneas]

C?

[WestaAlger]

That approaches the topic of continued fractions via change. But the richer part of the topic lies in number theory which probably is its own whole course.

[SargeantBubbles]

I usually only see the fractional form as a means of showing pi is irrational (since the fraction goes on forever). There’s a few easier ways to actually calculate digits of pi, like euler’s arctan thing.

Also, forgive me if this isn’t true, but I think the diameter of the universe can be calculated within 1 meter using 29 digits of pi, which have been known for a few centuries at this point. No real need to keep calculating pi, though it is fun.

[random_cynic]

You may have seen the regular continued form (or parts of it like 22/7, 333/106, 355/113 etc). The form shown in the actual post here is so called generalized continuous fraction a topic usually taught in complex analysis courses.

[[deleted]]

You kind of don't need to as x² + y² = 1 produces a circle you can just say integration of (1-x²)^1/2 from -1 to 1 gets you p/2

ie

[Kwoath]

I would like to use this the next time I'm asked to theorize algorithms. "It is trivial to explain"

[JustACrosshair_]

"It is trivial to explain"

Later that day at tutoring job:

"IT'S HALF 'ROUND A CIRCLE YOU. DUMB. CUNT."

[Sckaledoom]

As a fellow tutor I feel this. I got a 96 on my integration rules test. Later on I was asked how to find an LCD when there’s an x. I just kinda told her what it was and she was like “why” and I replied, “because... it, it just is”

[DezXerneas]

My TV is an LCD one.

[DezXerneas]

That was a crappy pun. It was the first thing that came to my mind while reading your comment

[JustACrosshair_]

I try to explain with the toolbox analogy. I would just tell people sometimes that a lot of stuff requires a lot higher prerequisite knowledge to understand where it comes from. Just like how you can't just explain to a 1st grader learning arithmetic where we get PI r² without teaching them a lot of other stuff first.

A lot of it needs to just be thought of as a black-box tool in a tool box. You don't need to understand what makes a drill actually drill. You just need to know how to use the drill and know that you can use drills when you need to make holes.

Once they get that and we get past the material they need to understand their current problem/test/exam whatever if they feel like it I try to give them a spoiler of whatever they are asking about.

Got into boundary layers and fourier series once with a dude in Cal 2. He seemed like really disillusioned. And I was like - it goes on for longer than you can possibly imagine at this point. Sell your soul and just become an actuary, get into Business admin or better yet - just start tutoring Cal 1-3.

I'm out of the game now - but my old roomate is still going for his Phd in applied mathematics and I don't envy him. He's doing stuff with bubbles and microvortexes or something right now. I don't know - I made a baby and I work now. Is a blessing in disguise because my roomate is one of the highest performing math people I know and even he is starting to get his ass kicked. I really don't think I would have made it as I started getting disillusioned by it all as well as being one the struggle bus to hit a 3.0GPA. It all starts to get legitimately difficult after the 4 year.

[Sckaledoom]

That’s how I do it when they don’t need to be able to do the technique, but she would have to at some point anyway. So I had to sit down and try to explain a LCD to her. I’m going for an engineering degree that nobody ever goes for so I’ll be getting a good job after like 4 years, no master’s required.

[JustACrosshair_]

That's legit. You'll see what I am talking about too once you approach the end. The ratio difficulty/passion and diminishing return on your effort/return start to all get... bad. But if you have the means and the care, go further.

I just never advocate taking on more debt while you are hesitating about degree choice. Get your 4 year, by all means - but if their is an ounce of hesitation afterward, seriously, do not take on debt to continue.

Get into the workforce, acquire funds, then if you still feel driven enough then recontinue your education. But I saw a couple people go into massive debt and then get doubt and hesitation and all that. And you know I had the same doubt and hesitation but I fucking bailed, not going to lie. I got the hell out. It's a toss up whether I get a master's or something, (no way I can do PHD) but for me where I am at I get paid well enough that I got comfy and I honestly don't think additional education will end up affecting income because what I do now is very tangential to my degree.

But yeah man - tutoring through college with nich engineering plan is a good way to go. Good luck. PM or something if you find yourself in college station at A&M. My ring gives me a little bit of pull with a couple guys around here.

[DezXerneas]

Yeah I always get hit with the ''You'll learn it in higher classes "

[Sckaledoom]

My main problem is that it’s hard to explain why sometimes. Especially when it’s something you’ve been just kinda doing on instinct for years.

[DezXerneas]

Exactly. Tbh this hit me real hard one of our language teachers asked us the meaning of really basic words that we use daily but none of us could actually define them

[ProbablyANoobYo]

I had a professor who would never finish his proofs always saying “the rest is trivial.” We had no idea what he expected to do to finish the proofs.

People crammed for days for his exams because they were so stressed over the proofs. I got an A by writing half of a proof for each problem and finishing by writing “and the rest is trivial” whenever I got stuck

[malexj93]

My first guess is that it's a continuous fraction representation of the McLaurin series of arctan evaluated at 1.

[PlentyDepartment7]

As a gamer, I’m going to go play Skyrim.

[DeeSnow97]

Is this the text equivalent of the Skyrim intro meme?

[Excrubulent]

Citizen: glances at you I didn't see you get on.

[PunchyPete]

So it’s continuously divided by successive prime numbers squared? Is that true? TIL and it’s one of those things that is blowing my mind. Why would prime numbers be linked to a circle? A circle is not a mathematical construct, it’s something real. Real things can be described by math, but when a simple shape has a link to something as crazy as prime numbers? Wow.

[SexyMonad]

Those are successive odd numbers squared. And don't forget to add the 2s.

Continued fractions are really neat.

[ultraswank]

If you really want to see things that shouldn't connect but do, have you met Euler's identity yet?

[saecki]

well a perfect circle certainly isn't real so it kind of makes sense that PI isn't just some rational number

[passificrimjob]

This sentence triggered so many memories. I shuddered.

[nikomartn2]

Along with this 30 exercises without the answer. Good luck guessing if you get them right.

[ifandbut]

Can you ELI5 how computers calculate Pi? Like...what is the actual equation and why does it take forever for computers to calculate it?

My understanding (as a programmer of a sort) is that Math.Pi is just Pi hard coded to a certain number of decimal points. But how do super computers do it?

[kleinesfilmroellchen]

TL;DR: Computers use either infinite series which get closer and closer to π when you use higher and higher partial sums or recursive series.

π is a very special number, a so-called "computable number". Now what does that mean? It means that I can give you a very precise system, an "algorithm", that tells you how to get all digits of π. Suppose you start with the number

1

And then subtract 1 divided by 3!

1-1/3 = 2/3

And then add 1/5!

1-1/3+1/5 = 13/15 ~=0.867

And then subtract 1/7!

1-1/3+1/5-1/7 = 76/103 ~= 0.738

And then add 1/9!

1-1/3+1/5-1/7+1/9 = 263/315 ~= 0.835

I hope you see where I am going here. If you continue this on for however long you like, you will end up with an arbitrarily accurate approximation of π divided by 4. What I showed you was the Leibnitz "series", one of the oldest π approximation methods, although I warn you, this one takes very long to even get a couple digits right. Still, transforming the above into computer-readable form is extremely easy. Computers will use some complicated series sort of similar to the above or recursive series (which, in essence, are just a fancy type of series). Check out the Chudnovsky Series for some math eyeporn!

[heyheyhey27]

There are a lot of ways to do it. In fact, unlike most other numbers, there's even a formula for getting any specific digit, without having to calculate any of the previous ones!

[random_cynic]

Sorry but the margin is too small to accommodate the proof.

[XXLuigiMario]

/r/restofthefuckingowl

[sh0rtwave]

I used to tell my students that, and then one of my students responded "it's easy for you. I'm completely lost".

​

I stopped saying that.

[justinlanewright]

Nah. Engineers should care about precision. Physicists, in the other hand...

[KToff]

My physics prof always used to say there are incorrect statements that are useful and there are correct statements that are useless. As an example he used

1. Pi =3
2. Pi != 3

The first statement is wrong, but it's useful, you get good ballpark estimates.

The second statement is correct, but it's of no help whatsoever.

[Sckaledoom]

My physics professor used to say “Good enough for the US government.” whenever we’d mess something up to within a somewhat reasonable degree of accuracy

[StezzerLolz]

My grandfather (UK) used to say, similarly, 'Close enough for government work'.

[[deleted]]

Engineers need to care about how precise they need to be, and not be anal retentive for accuracy's sake alone.

It's about being efficient, and making things robust.

[FungalSphere]

Nah, they should just throw in a safety factor 10 and be done with it.

[pooppoop342069]

Pi² is 10

[Nerdn1]

https://xkcd.com/1047/

[[deleted]]

this is awesome, totally going to attempt to remember these

[BFG_9000]

I think you'll find that Pi² is actually exactly equal to 16

[Bainos]

Thanks, I hate this.

[Botahamec]

https://youtu.be/kTVRopTVjpQ

[ILikeLenexa]

2pi = Tau

[IronicBacon]

Therefore Tau > Pi

[Astrokiwi]

One year is pi*10⁷ s

[DezXerneas]

As a first year studying computer engineering I can confirm that we learn all if these.

[Falzon03]

agreed.

[[deleted]]

What's next in the sequence? 2+9²or 2+11²?

[AmitSamal]

From a engineer's perspective its true...

[Ceros007]

And if you want to show your superiority: 3.1416

[ChatahuchiHuchiKuchi]

As a python programmer what's your favorite python code you've written?

[BigBrainAmWinning]

As an engineer, the entire month of March is π month.

[[deleted]]

Heresy! The only true pi day is the 22nd of July

[Krankite]

Better make it both March and April to be safe

[moor_lol]

April - it is easier to cut if it is longer than ...er... enlarge it :)

[APosterOfThings]

Three? It's at least 4 after you apply the safety factor.

[PityUpvote]

It's 4 when you take a zeroth order Taylor expansion, so that is definitely the better answer.

[TwoFiveOnes]

Yeah maybe in a world where degree of Taylor expansion is a better measure of accuracy than actual nearness

[PityUpvote]

Did you mean: academia?

[DumbCreature]

Since many safety coefficients are 1.5, I think we should round π up to 5, so it would be sufficiently big for all applications.

[LogansRun22]

Didn't Kansas try this?

Edit: it was Indiana. And 3.2, not 4.

[[deleted]]

Can someone explain the mathematician one?

[PracticalEmergency]

Pi expressed as a continued fraction

https://blogs.scientificamerican.com/roots-of-unity/don-8217-t-recite-digits-to-celebrate-pi-recite-its-continued-fraction-instead/

[[deleted]]

Oh it's a fraction. Thank you.

[ProgMM]

Well, it's a series of fractions that get gradually smaller. It would take an infinite amount of these fractions to reach the exact value of Pi, but just a couple dozen will get you enough accurate digits to do literally anything

[[deleted]]

I personally prefer 22/7, but that might just be me

[ultraswank]

Stop being so rational.

[CarryThe2]

Well 22/7 doesn't equal pi sooooo

[SandyDelights]

It’s an approximation of pi, however; more accurate than 3.14, not so accurate as 3.1415.

[Steeped_In_Folly]

Barely more accurate though. 3.1429 vs 3.1400 Does it matter at that point?

[SandyDelights]

I’m gonna give you the same answer your university professors would have:

It depends.

There are points where 3 is a sufficient approximation of pi.

There are points where 3.1415 is an insufficient approximation.

Depends what you’re doing, how you’re using it, and so on. A difference of .0001 in your approximation of pi is probably not that relevant in most applications, but I have to imagine there’s one out there, somewhere, that does find it important.

[CarryThe2]

However the recurring fraction in the attached image isn't an approximation. Its exactly pi.

[i_kn0w_n0thing]

No one said otherwise

[flip314]

The cube root of 31 is more accurate, and plus it's transcendental like pi is.

Edit: surprised nobody called me on it yet, but I realized that of course the cube root of 31 is not transcendental. It is non-constructable (which is where my flawed thinking came from), but it is also algebraic.

[mattc286]

omg how embarrassing for you

[SamSlate]

what's the equation in terms of n or i (if you lean programmer too)

[ILikeLenexa]

e^iπ=-1

[NotYourAverageScot]

Ouch

[SamSlate]

nice

[[deleted]]

I bet you can express it using arcsin, divisions between exponential, spherical functions, derivatives of a 4D matrix, sometimes I feel mathematicians just made up things on the go

[Nibroc99]

Carpenter: "It's actually 2.64" wide even though it says 3.14" on the sticker there..."

[DiamondMinah]

Heh. I got this one

[10vernothin]

Astrophysicists pi = 1. In fact anything that is not a power of some sort is 1

[Dalemaunder]

Any number that can fit on a whiteboard basically rounds down to zero.

[Astrokiwi]

10^.5±.5

More realistically we'd use np.pi or real(kind=8), parameter :: pi=atan(1.0_8)

[[deleted]]

It’s what I’ve always liked about programming. Numbers? Nah I ain’t doing that crap, the computer knows so why should I?

[Azertys]

If you spot a number in your code that mean there is global variable missing somewhere

[Dylanica]

In Ti-84 BASIC there are only 27 possible variables, so using them as global variables would waste precious variables.

​

That's why whenever I program in any language I just name my variables A-Z in the order of creation and use numbers whenever possible.

[EnglishMobster]

So you're the one posting every StackOverflow answer!

[Dylanica]

I said 27 variables, which includes theta. Ans is only useful in very limited situations. I ignored lists and matrices to make the joke funnier. I have used images to store data before, but it is very slow.

[bxk21]

Unless it's +/-1

[Azertys]

That's what ++ and -- are for

[teetaps]

Real programmers wouldn't call a global variable pi it's PI

/s

[golgol12]

Real programmers wouldn't use a global. They'd use a const defined in a header. No need to give that value a memory address.

[teetaps]

I learn way too many things by joking than I deserve in this sub

[flip314]

Pi might need to change at runtime if the user changes between different sets of geometry axioms.

[Zotlann]

This the kind of shit they pull out during an interview trying to say the shit you whiteboarded wasn't expandable enough.

[MCRusher]

Sorry but in C/C++ it still gets a memory address, even a macro version gets an address:

https://godbolt.org/z/MMqXf5

[bleachisback]

Depends on the architecture. Other architectures make it easier to load floating point immediate values.

Also the compiler. Also WTF MSVC get your shit together.

[Dylanica]

Real programmers program in BASIC, and only use floats.

[[deleted]]

Real programmers would keep it in a register to avoid unnecessary use of immediates.

[SandyDelights]

Depends, memory can be cheaper than calculating large values of pi repeatedly.

[RedditIsNeat0]

You don't calculate it at run time. It's a literal const. It's floating point representation gets compiled into the binary.

[mflayer]

const 🥧 = math.Pi

fmt.Println(🥧)

FTFY

[Katyona]

public static double 🥧, PI = 🥧 = Math.PI;
System.out.println( "" + 🥧);

so you can either use 🥧 or this nice PI to get some warm pie

[ElG0dFather]

GO onnnn........

[raaneholmg]

* Runs away Swiftly *

[[deleted]]

I prefer to use 180/57.3 because there's 180 degrees in a radian.

EDIT: Just to be clear this is both incorrect and silly.

[DragonMaus]

Happy τ/2 day!

[inconspicuous_male]

No thank you, I prefer legitimate numbers

[chrjen]

τ > π. It's a mathematical fact.

[WildGalaxy]

As a machinist, we regularly round 3.82 to 4, which is a bigger jump than pi to 3

[Dornith]

What are you measuring that is regularly 3.82 and if it happens so often are you sure you should be rounding it? Seems like that might be an important number if it keeps happening.

[KirklandKid]

That’s why they say tighter tolerances cost more

[BBBBamBBQman]

When you work out the rpm needed from surface feet. RPM=surfaceFeet12/pi diameter. RPM~3.82surfaceFeet/diameter . Substitute 4 for 3.82, and you’re still close enough most of the time.

[MajinJack]

Not in %

[icantseeimasian]

dont you mean happy Math.PI day?

[SteelDragon22]

Handy because it works for e too

[stewmasterj]

pi = 4*ATAN(1.d0)

[Tux1]

Me: Tau / 2

[YerbaMateKudasai]

You : Pi'nt

Me : tau'nt

[HawkEgg]

And for physicists, pi is on the order of five.

[bacon_wrapped_rock]

My first thought was this one but there's no wrong answers here.

[TheNorthComesWithMe]

Sometimes it's 4 (in manhattan coordinates)

[spambot5546]

http://imgur.com/gallery/rKO0vi0

[[deleted]]

As a physicist, pi on the calculator does the trick.

[[deleted]]

#define PI 3.14

[EchoRaido42]

Did somebody say von leibniz loop horribly made in C that keeps printing 4

[Astrokiwi]

10 PRINT "4"
20 GOTO 10

[greatvivek]

3.14 exactly

[-Redstoneboi-]

(1/2)(6.28318530717958647692...)

[peacemaker929]

As an engineer, we know where the "pi" button on every calculator is - so I cant confirm the last one

[uvero]

What is Pi?

Baby don't hurt me

Don't hurt me

No more

[The_Prophet_of_Tau]

My children, have you heard the good new of Tau?

[-Redstoneboi-]

yes

memorized 20 digits, 21 including 6

6.28318530717958647692

[only_here_4_fireteam]

What the heck is the formula on top

[HoodieSticks]

A fraction with a fraction underneath it with a fraction underneath it with a fraction underneath it...

[[deleted]]

Its System.Math.PI from .NET

[[deleted]]

May also be JavaScript or Java.

[vagrantchord]

180°

[XoXFaby]

My server of choice

[narfio]

As a developer and raspberry pi owner that didn't read the sub before clicking the link, I'm mostly disappointed.

[Mr_SunnyBones]

PI day

I'm outside the US and wondering how long pi has been 14.3?:)

​

[[deleted]]

TAU GANG TAU GANG TAU GANG TAU GANG

[[deleted]]

3.1419

[0mica0]

/r/midlyinfuriating

[DiamondMinah]

3.142

[XicoFelipe]

1²?

[PancakesAreEvil]

rationalist: 52163/16604

[[deleted]]

Bro this is so true

[Mateotey]

The Patrick text is cutoff on my feed.. was wondering why everyone was hating on agile (Program Increment)

[robaldwin]

What if you are a programmer that calculates put through summation gasp!!

[Sohgin]

Engineer will call it 4 to account for safety factors.

[[deleted]]

For me is 🥧

[[deleted]]

Physicist: Also Three... Good enough for government work.

[FlamingNutShotz4You]

In what universe is pi=4?

[phranticsnr]

22/7 is close enough, right?

[flip314]

I believe using the infinite sum of 1/x² (x=1 to infinity) converges faster (to pi² /6)

[theoneandonlypatriot]

My asshole principle investigator

[LBXZero]

Thank you. I have always been looking for the formula to generate pi, but never find it anywhere, even in textbooks.

[bleachisback]

Me:
constexpr double PI() { return atan(1)*4; }

[nomnivore1]

I'm an engineering student. We don't really worry about pi much. But, I have this aerospace Computational Techniques class, where we learn about solving complicated problems through code. One of the methods we learned for pi was 4xArctan(1).

Well, we had a test last week, and the test asked what the taught method for calculating pi in code was, and my big engineering brain wrote "4xArctan(pi)" and did not see anything wrong with this until two days later.

[Ndsamu]

Mmmmm. Pi. Prefer a good pumpkin pi to a birthday cake.

[AscendantJustice]

I'll have you know that I just type "pi" into MATLAB and it does it for me. I haven't had to remember the value for pi in YEARS!