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From: Vihart
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  • 0:17 Pi is the ratio of the circumference of a circle to its diameter, b/a, not a/b

  • i came here for the pie

  • Math - it works, bitches.

  • Oh, god, not a tau video. I'm so sick of people trying to argue for tau. There are plenty of situations which make tau just as unreasonable.

  • @JVP3122 Which situations?

  • @JVP3122 Yes, please elaborate. I need valid arguments for maintaining my memory of the first bunch of digits of pi >:3

  • I just came from the bar and typed ancient and ended up here. I'm confused right but I'll add this to my favorites and see it when I wake up. It made sense with the volume down.

  • She kinda reminds me of Lisa Simpsons!

    Subbed!!

  • Ghazuntai.

  • Ok pause the video at 2:45.

    Now notice how the sine wave crosses at pi and 2pi.

    Next notice how a nicely drawn circle can fit in each of the half of the sine wave, with coincidentally the diameter pi.

    Finally, realize that although it is not wrong to create variables in math, the usefulness of such a declaration is minimal at best and pointless at worst.

  • Pi-Winning.

  • NO! You need to make a tau! I don't know what it would be or how it would taste, but you need to make one!

  • OH MY GOD thank you so much trig is now making so much more sense.

  • there has been some massive push-back from pi conservatives. they claim that tau is in fact wrong for complicated mathematics. my view is that mathematics is rife with cheap constants specifically invented to make the work easy. ergo use tau where tau makes sense and use pi where pi makes sense. don't needlessly complicate the learning process of children for the sake of your ego.

  • who cares if its tau or pi, both aren't exact numbers. Just one of tons of expamples: in electronics you often calculate with half of the sinus/cos wave...so we are at tau/2 again :) It's a demonic circle.

  • better solution : leave mathematics basics alone and change the literature meaning of pie:

    change what is known as 'pie' now to 'twopie', and make a half circle = pie

  • @talanhawke totally agree, but try telling that to my math teacher...

  • Nine years ago, I was attending the last year of high school, and last math class of my entire life, and we studied trigonometry that year (my school was a literature and dead languages and philosphy and things that officially have nothing to do with science one, so our math classes were slow). Well, I didn't understand one single thing. Just memorized something and cribbed the rest. Now, thanks to you, I understood something! At least, something.

  • SHE CAN COOK???!!!

  • Also, one last thing... celebrating BOTH days means twice the pi.

    I did the math, and that is definitely twice as awesome.

  • @talanhawke Actually, its 3x the pie.

  • "The way of mathematics is to make stuff up and see what happens."

    Yep.

  • Damn it. Now I want two pi(es).

  • Now I want pie...

  • pi-winning

  • oh and + you have a snail.....

  • please be my match teacher.. i wanna be smart

  • At least she is in the kitchen.

  • area = (r^2*T)/2? perhaps pi is useful for defining the area

  • "lovely tou" haha wow this got confusing fast. I would love to see her show a teacher how Pi is wrong. try hard?

  • I WANNA MARRY HER *tears of happiness*

  • I mean i'd rather not have to find the area of a circle with .5Tr^2.

  • @TheMrClamberto I'd rather not have to find the kinetic energy with .5mv^2, or elastic energy with .5Cx^2, or the change in position with .5gt^2. Most quadratics that come up in any realistic scenario have a factor of 1/2 attached, because integrating a power function always introduces a factor of 1/(n + 1).

  • @ianmathwiz7 In physics you get a calculator; in calculus class you don't.

  • @TheMrClamberto First, pi*r^2 isn't calculus. Second, what about the formula for sector area, .5*theta*r^2? It's not just physics. Third, what calculus classes have you been taking? They at least gave my class calculators. Finally, most formulae in calculus that use pi actually become simpler with tau, e.g. Fourier transforms, Cauchy's integral, and the normalized Gaussian.

  • Maybe for a mathematician changing 2 pi with tau is not a big deal. After all that's what mathematics is for: expressing things in different ways so that you can take the simplest path of solving a problem. And that's exactly why there should be a 2 pi equivalent. Lots of units are introduced the same way, like radians for example. Why do we use radians and not degrees? It's after all the same thing: an angle! It's just for convinience. Why do we say 2 hours and not 120 minutes. It's all the sam

  • Never heard tau is supported in math.h!

    Here comes pi: #define M_PI 3.14159265358979323846

    And this is what tau should be: tau = 2 * M_PI;

    So, I will never forget pi!

  • @loliraki I will use this the next time I code

  • While you make a strong argument for tau in some cases, you haven't considered all the cases like area. I agree we can use tau to make some mathematical concepts more concrete but we should use pi still because it also makes some math concepts more concrete than tau can and would.

  • @someonenot2 Read the website she links to; it addresses that objection. Basically, saying A = 1/2*tau*r^2 actually makes more sense, since most quadratics that you find in nature have a 1/2 attached to them, since integrating a power function always introduces a factor of 1/2.

  • have your pi and eat it tau

  • Born on Tau Day, aaawwww yeaaahhhh.

  • @TimePanda I just realized that I was too! :D

  • You are not eating the circunference, you're eating the entire volume of the pie. If you associate it with the height times the base area (and the radius still 1), you'd get:

    V=h*pi*1²

    V=h*pi

    half a pie?

    1/2*V=h*pi/2

    one-third of pie?

    1/3*V=h*pi/3

    And that's why pi is still better, at least in your example.

    (sorry for bad english, I'm Brazilian)

    Love your videos, btw!

  • @jhlarcher She's measuring in radians, since that form of measurement works regardless of the size of the pie.

  • im in 8th grade, and next year, when i take trigonometry, i am so arguing this...

  • @rjqg327 im in 8th grade and im taking trigonometry. ADVANCED

  • @rjqg327 to show, that you can substitute 2pi as another variable? call is x,y,x,z...etc. makes not difference. Pi is fine. pi better. It is like saying "lets call 2e as l!"

  • @rjqg327 whaaaat a douche you are

  • @rjqg327

    you arnt gonna see the use of tau for a while

  • You are like Martha Stewart (baking and drawing) + Mathematical skills + Musical skills!

  • this is not so impressive. Yipee. I get another letter represent 2pi. How can i benefit really? save the time to write two pi. The unit circle as tau doesn't benefit me greatly. It will not help me in anything really. Unless it contributes something useful to differential geometry or diff equations. i am listening. pi is the ration of the circumference of a circle to its diameter. The only wrong thing here is the amount of butter in that pie.

  • @darthmath2

    You haven't really worked with radians, have you. It's so annoying that pi/2 radians is 1/4 of a circle and pi is just half of it. It's like taking to halves to define an object rather that define it as one whole. Imagine if you had to say "I've got two halves of an apple". It's just unnecessarily confusing and obscure.

  • Haven't really worked with radians? Seriously? I am a undergraduate mathematics major, why wouldn't I work with radians.

    Even I as a mathematics major. Who does mathematics for fun. Does proof after proof. Break my head to wrap my mind around abstract concepts. I do not find this interesting. It is just tau. I use tau as a dummy variable (like x,y,z, etc). I took this in high school, and it was simple. Nothing was difficult. Even students i tutor don't get annoyed

  • @darthmath2 As a fellow math major, who also does math for fun, I find replacing pi with tau incredibly interesting. For me, it's about the beauty of equations, and tau makes so many more identities beautiful.

  • @ianmathwiz7 For me, i see no beauty in it. Like that gaussian integral, the area under that curve would change from sqrt(pi) to sqrt(1/2tau). I mean no profound meaning there. Oh well. That is just me. At least we find mathematics as a whole lovely. I like number theory alot. and differential geometry. and those differential equations (ordinary so far). isn't it awesome? lol. I can't wait to go to graduate school!

  • @darthmath2 The integral itself might have that, but I find myself using the normalized Gaussian much more; in that version, you have a factor of sqrt(2pi) = sqrt(tau) in the normalization constant.

    My favourite branches of mathematics would have to be complex analysis and graph theory.

  • "I'll be making tau, and eating two."

    Best quote ever.

  • The thing is, guys, Tau isn't replacing pi. Even if tau starts becoming common use, you can still use pi whenever you want. There are some equations in which pi is a better number to use, so use it then, if you want, but in more cases than not, tau makes math easier. It's not redefining math, just making it more simple when it's appropriate.

  • Are You Lesley Winkle?

  • what was the point of writing in french

  • That's a very buttery pi pie

  • The Pie is a lie

  • wow vihart u r the perfect women!!!! mathematician, musician, u draw and now u cook!!! and i guess that u r pretty <.<

  • Were the pies good?

  • I used tau to label my sin wave values on a pre calc test over the unit circle and stuuf. I got full credit -:

  • @eggs111 That's because you have a math teacher that know's what's up, Enjoy it while you can.

  • Also, the radius is used to define the radian.

    Really, if we're using the diameter to define the circle constant, which can be used to determine the number of radians in a circle, the radian should also be defined by the diameter.

    Should the radian should be the diamian :S ?

    It's all so stupid!

    TAU TO THE RESCUE !

  • @eedes100 pi diamians in a circle, tau radians in a circle

  • Now I'm hungry. Thanks.

    At least I learned something :)

  • SO I WASN'T STUPID.

  • But Vi that seems rather arberchary, Sure Tau makes radiant easier but it would be annoying to convert between pi and tau every time you want to work out radiance

  • I especially like the way you leave out a unit of measure and abuse homonyms to try and make your point. Is the logic not good enough on it's own?

    yes, doubling pi and giving it the value tau simplifies some things, so does saying 2 instead of 2(1).

  • Check 3:55 out!

  • In these comments: High schoolers who got D's in basic trigonometry.

  • I love your channel! You have got to be one of my favorite Youtubers! Keep up the amazing math videos!

  • tau would be the worst idea ever if you use that symbol anyways.... in the engineering field that is already over used to hell I dont need some stupid asshole to come out and say HEYY LETS USE TAU INSTEAD OF PI!!! no... unless you can come up with an another 'elegant' symbol (good luck) for tau stfu k thx

  • @ZixacunX whoa whoa whoa, chill man, get laid by a hooker or smoke a doobie, but don't claim a field owns a letter, that's just dumb.

  • @AverageJoe8686 Engineering doesnt own the letters... but engineering is pretty much where these shit thrive

  • all the people who liked this video are probably junior high or elementary students who dont like math...... or just anyone who sucks at math

  • Aw, why do we have hate of Pi so much? Come on guys, surely this is like saying Pluto isn't a planet anymore, are we really going to say Pi is no longer a number? :(

  • @nturneta that's not what she's saying at all.

  • OMG yhu are SO brilliant I LOVE YOU!!!

  • τ is taf not tau

  • i feel stupid...

  • I'm going to memorize this and copy it word for word, doodle for doodle and confuse the shit out of my math teacher.

  • what?

  • you, knowing what you know, SHOULD GO ON MORE ABOUT THE TRUTH, THAT HAS BEEN HIDDEN , this math you talk about, THERE IS MORE ABUOT SACRED GEOMETRY THAN WE WILL EVER KNOW, more has been hidden about TRUE MATHETMATICS, than almost anything in history, THE PEOPLE WHO HOLD THE KEY TO THE SECRET, HOLD ON VERY VERY TIGHTLY

  • IT IS NOT A MISTAKE, IT;S ON PURPOSE

  • The Pi(e) is a lie!

  • f pi

  • MUST FIND RECIPE FOR PIE MADE HERE

  • watching this video ignoring my geometry home work and eating apple pie ^.^

  • i think that you've mistaken the unit circle for being an area but it's actually the circumference which is 2(pi)r, and since the radius of the unit circle is 1 than it makes perfect sense that it is 2pi

  • @MeTalOZDC The main point that she is making is that pi is the ratio of a circle's diameter to its circumference, yet it is a radius that defines a circle, not its diameter. Therefore, if we take the number tau, and define it as the ratio of a circle's radius to its diameter, it makes things simpler. The circumference of a circle is now (tau)r, therefore all the way around the unit circle is now tau radians.

  • "Ceci n'est pas une pi." I love it!

  • although this one instance in which you use pi "tau" would be a lot nicer, but in later mathematics courses it's a lot nicer to write "pi" when you need it than "(tau)/2"

  • Change Pi to Tau is more to confuse people that learnt pi. And who should change all the math books xD?

  • Wat just happen? :)

  •  THE PIE LOOKS DELICIOUS.......

  • Haha, I don't know whether you're really serious about this, but Tau wouldn't be more logical or simpler. Pi is that ratio, not Tau. So you'd only add a new constant which doesn't even do that much. It's not simple if you add unnecessary crap! :)

  • Okay,I am having a heard enough time in math as it is... I am now even more confused...

  • @crazycar543 Apparently you are struggling in English too

  • But a circle isn't "2 pi". What does that even mean? If you want an eighth of a circular pie, that slice's area is pi*r^2/8 , not pi/16 ... Right? I mean, what?

  • 1:38 Fench lol I'm a French Subscriber !

  • Well its not about the tyrany(:P) of pi and the opulence for using tau.

    It is more for remind us the past and the origin of trigonometry-->analysis etc.

    wich all started from geometry.π(pi) represented one of the most hard problems of ancient geometry ->squaring the circle.Tau is a very good idea but i think pi is more respectable for beeing used.

  • 3.141592653589793238462(etc.)

  • im pi-winning

  • That looks sooooo delicious

  • man, i'm in geometry and i thought that was difficult...

  • i wish i could make a pie from scratch like that....

  • e to the i to the e i o is e to the wau to the tau wau wau.

  • I don't get it. I probably never will. I have the exact opposite brain as you. But that's cool, because I love you anyway.

  • It's time for a change

  • LOL Dradians

  • this is all very interesting but i am only in year 5 maths so i dont really understand :(

  • Don't make pie. Make tart ^_^

  • That's a looooot of butter!

  • It's so simple, with tau being 2 time pi, but it's obviously way better and COOLER.

  • I would like you to be my teacher.

  • i like Pi, but i like Tau more, cuz if i choose Tau, i get 2 pies

  • @p00pkrap If you choose Tau, you get one pie, or two π's.

  • @nxkr3w Pie or π, it still sounds delicious. i'm fine with either. wanna share?

  • @p00pkrap No.

  • good to see she's in the kitchen.

  • I have nothing against using tau instead of 2pi other than the fact that tau is already in use in many engineering disciplines for other values, not the least of which is the RC time constant for electrical circuits. I vote that we have a new symbol and name for 2pi. I suggest the value vi. 2pi = vi. The symbol will be a stylized V and Vi Hart can design it. Who's with me on this?

  • I just zoned out about a fourth of the way there, I'm sorry :l

  • You lost me when you the pie left the screen. Now I am confused and hungry.

  • it's because the circumference is 2π•r. The unit circle has a radius usually defined as one, though radians are a proportion of the radius to the arc length. However, if the radius *were* 1, the circumference of the circle would be 2π.

  • The tau argument has some good points, but in terms of real-world applications, if you attempt to take a measurement of an existing circular object (or void) you're going to measure the diameter. Not the radius.

  • @JonMW Not having to divide by two when you measure diameters is surely less beneficial than Trig/Precal's pedagogy improving vastly, formulas simplifying and making more intuitive sense, and the benefit of seeing a single turn as constant rather than a constant times 2. Even (1/2)pi*r^2 is conceptually more intuitive than pi*r^2.

  • ok... now I have to watch it again and see if I can catch up XD

  • genius is to petty a word to describe your mind

  • Technically, you would have to go to the end of pi to find out what pi times two is.... 

    3.1415926535897932384626433832­79502884197169399. Ect... Not that it's possible.

  • what????????????????????

  • I wonder what my math teacher will think if I write tau instead of pi on my test... oh well, guess I'll do it!

  • @juntie9 or it could be an AP prank for math :P

  • Hey, just wondering... what is your recipe for pie? ^.^;

    Just wondering, because, well, it looks delicious.

  • lmao PI-WINNING!

  • Mathematics graduate here... to those saying this is too complicated and should be simplified, this is high school math, you should know this, math gets way more complicated than this. Vihart, this is fantastic, I love all of your videos, you are doing a great service in teaching people how math can be fun and extremely interesting. Thank you.

  • You probably shouldn't use such hard equations when explaining this concept because I'm pretty sure 90% of you audience probably have no clue what you are talking about. It's like saying dihydrogen monoxide, most people don't know what that is even though they see it everyday. You should simplify thing more, just saying.

  • Hay I doodle in math and my teacher teaches us stuff that is stupid and we all ready know

  • One word... WHAT?!?!?

  • I learnt this when learning about radians?

  • I don't think my brain can repair from this....

  • i like pie

  • 360 degrees ^^

  • at 0:18 im pretty sure 'b/a' = pi

    other than that i totally agree on tau

  • wait... i lost you at 0:00

  • Can you come teach our school math?

  • Mind = blow

  • @LegoNinjaagoTurtle

    Oxygen+Potassium would make potassium oxide

  • @Shadow10975 The chemical formula of LSD is C20H25N3O.

  • Oxygen Potassium....

    Chen=ck the periodic table ^.^

  • you do realize that Euler's gonna be pissed...

  • Now im hungry i need to eat pie

  • now every time my teacher does radians and trig. I keep hearing this in my head, and thinking that it could be sooo much easier with tau!

  • just a interesting fact theta in spanish sounds the same as teta with in english means "tit" so everytime my professor is teaching everybody laugh

  • You just explained the whole trigonometry thing to me again and made me see why tau would actually make more sense. I completely agree with you!

  • ok, after watching this twice, i got it, pi is confusing as you say, because it was first calculated using the diameter, why? because in that time, seemed good. so the convention of using pi acording to the diameter is because at that time diameter seemed better, so, math continued developing over pi. its like temperature scales, why do we use fahrenheit and celsius, if the really "natural" and universal scale is the kelvin? because it's conventional.

  • My teacher got mad at me cuz she didn't know what tao is

  • Hey guys.. watch out, we got ourselves a badass over here!

  • so r u sure ur not asian?

  • Euler's Identity can still have 5 important numbers with tau: e^(iτ) = 1 + 0. That zero isn't randomly added there; it's really part of the identity. e^(iθ) = cos(θ) + isin(θ) → e^(iτ) = cos(τ) + isin(τ) → e^(iτ) = 1 + 0. I think it strengthens the argument.  The way they do it with π is cheating.

  • what is your job?

  • holy moly, the confusion is in your head, seriously, pi is a constant, period. any doubts? now, you should blame either your teacher or your book, but not the whole math just because you think using another latter is easier. by the way, we kind are runing low on greek letters, physics already uses all of them, and you still want to give more meanings to them? now thats the confusing part

  • erm HELP!

  • I could go for a slice of cherry tau right about now.

  • I cant understand a word she said..

  • Can I have the lyrics to this song?

    I mean um this story...I mean this lesson?