The infinite life of pi - Reynaldo Lopes

Beskonačan život broja pi - Rejnaldo Lopez (Reynaldo Lopes)

1,604,310 views ・ 2013-07-10

TED-Ed


Please double-click on the English subtitles below to play the video.

Prevodilac: Jasna Andjelkovic Lektor: Mile Živković
00:13
Try to measure a circle.
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Pokušajte da izmerite krug.
00:15
The diameter and radius are easy,
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Sa prečnikom i poluprečnikom je lako,
00:17
they're just straight lines
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to su jednostavne prave linije
00:18
you can measure with a ruler.
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koje možete izmeriti lenjirom.
00:20
But to get the circumference,
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Ali da biste dobili obim kruga,
00:21
you'd need measuring tape or a piece of string,
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treba vam metar ili uže,
00:24
unless there was a better way.
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osim ako ne postoji bolji način.
00:26
Now, it's obvious
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Dakle, jasno je
00:27
that a circle's circumference would get smaller or larger
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da obim kruga postaje manji ili veći
00:30
along with its diameter,
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zajedno sa njegovim prečnikom,
00:32
but the relationship goes further than that.
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ali ta vezanost seže dalje.
00:34
In fact, the ratio between the two,
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Zapravo, odnos ove dve mere
00:36
the circumference divided by the diameter,
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je takav da se deljenjem obima kruga sa njegovim prečnikom
00:39
will always be the same number,
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uvek dobija isti broj,
00:41
no matter how big or small the circle gets.
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ma koliko krug bio mali ili veliki.
00:44
Historians aren't sure when or how
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Istoričari nisu sigurni kada niti kako
00:46
this number was first discovered,
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je ovaj broj prvi put otkriven,
00:48
but it's been known in some form
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ali je poznat u nekom obliku
00:50
for almost 4,000 years.
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već 4.000 godina.
00:53
Estimates of it appear in the works of ancient Greek,
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Procene ovog broja javljaju se u delima antičkih Grka,
00:55
Babylonian,
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Vavilonaca,
00:56
Chinese,
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Kineza,
00:57
and Indian mathematicians.
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i indijskih matematičara.
00:59
And it's even believed to have been used
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A veruje se čak i da je korišćen
pri izgradnji egipatskih piramida.
01:01
in building the Egyptian pyramids.
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01:03
Mathematicians estimated it
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Matematičari su ga izračunavali
01:04
by inscribing polygons in circles.
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ucrtavanjem mnogougla unutar kruga.
01:07
And by the year 1400,
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A do godine 1400.,
01:09
it had been calculated to as far as ten decimal places.
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proračunat je do desetog decimalnog broja.
01:13
So, when did they finally figure out the exact value
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Dakle, kada su konačno otkrili njegovu tačnu vrednost
01:15
instead of just estimating?
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umesto približne?
01:17
Actually, never!
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Zapravo, nikad!
01:20
You see, the ratio
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Znate, odnos
01:21
of a circle's circumference to its diameter
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obima kruga i njegovog prečnika
01:24
is what's known as an irrational number,
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poznat je kao iracionalan broj,
01:26
one that can never be expressed
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koji nikad ne može biti prikazan
01:28
as a ratio of two whole numbers.
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kao razlomak dva cela broja.
01:31
You can come close,
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Možete biti približno tačni,
01:33
but no matter how precise the fraction is,
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ali bez obzira koliko je precizan deo,
01:35
it will always be just a tiny bit off.
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uvek će nedostajati još samo malo.
01:38
So, to write it out in its decimal form,
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Te, da biste broj zapisali u decimalnom obliku,
01:40
you'd have an on-going series of digits
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morate imati niz cifara
01:42
starting with
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koje počinju sa:
01:43
3.14159
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3,14159
01:46
and continuing
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a nastavlja se
01:47
forever!
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beskonačno!
01:49
That's why, instead of trying to write out
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Stoga, umesto pokušavanja da zapišemo
01:51
an infinite number of digits every time,
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svaki put ovako beskrajan niz cifara,
01:53
we just refer to it using the Greek letter pi.
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pribegavamo upotrebi grčkog slova pi.
01:57
Nowadays, we test the speed of computers
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Danas, ispitujemo brzinu kompjutera
01:59
by having them calculate pi,
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tako što im zadajemo proračun broja pi,
02:01
and quantum computers have been able
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i izvesan broj kompjutera uspeva
02:03
to calculate it up to two quadrillion digits.
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da izračuna i do dva kvadriliona decimala.
02:06
People even compete to see
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Ljudi se takmiče
02:08
how many digits they can memorize
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u pamćenju što većeg broja cifara,
02:09
and have set records for remembering
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a postavljen je rekord u pamćenju
02:11
over 67,000 of them.
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koji prelazi 67.000 cifara.
02:15
But for most scientific uses,
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U najvećem broju slučajeva za potrebe nauke,
02:16
you only need the first forty or so.
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potrebno nam je prosečno oko 40 cifara.
02:19
And what are these scientific uses?
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I za koje to naučne potrebe se koristi?
02:21
Well, just about any calculations involving circles,
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Pa, za skoro sve proračune koji uključuju krugove,
02:25
from the volume of a can of soda
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od računanja zapremine limenke soka,
02:27
to the orbits of satellites.
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do putanje satelita.
02:29
And it's not just circles, either.
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I to ne samo kada imamo krugove.
02:30
Because it's also useful in studying curves,
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Budući da se koristi i u izučavanju krivih linija,
02:33
pi helps us understand periodic or oscillating systems
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Pi nam pomaže da razumemo periodične ili oscilatorne sisteme
02:36
like clocks,
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kao što su satovi,
02:37
electromagnetic waves,
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elektromagnetni talasi,
02:39
and even music.
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pa čak i muziku.
02:40
In statistics, pi is used in the equation
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U statistici, pi se upotrebljava u jednačini
02:43
to calculate the area under a normal distribution curve,
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pri izračunavanju površine ispod krive linije sa normalnom raspodelom,
02:46
which comes in handy for figuring out distributions
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što je zgodno pri utvrđivanju raspodele
02:48
of standardized test scores,
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testova standardizovanih rezultata,
02:50
financial models,
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finansijskih modula,
02:51
or margins of error in scientific results.
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ili graničnih grešaka u naučnim rezultatima.
02:54
As if that weren't enough,
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Kao da to nije bilo dovoljno,
02:55
pi is used in particle physics experiments,
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Pi se koristi u eksperimentima nad česticama u fizici,
02:58
such as those using the Large Hadron Collider,
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kao što je slučaj u korišćenju Velikog hadronskog akceleratora čestica,
03:01
not only due to its round shape,
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ne samo zbog okruglog oblika,
03:03
but more subtly,
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već i iz suptilnijih razloga,
03:04
because of the orbits in which tiny particles move.
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zbog putanja kojima se te majušne čestice kreću.
03:07
Scientists have even used pi
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Naučnici pi koriste čak i
03:09
to prove the illusive notion
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za dokazivanje iluzorne pojave
03:11
that light functions as both a particle
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svetla koje funkcioniše i kao čestica
03:13
and an electromagnetic wave,
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i kao elektromagnetni talas,
03:16
and, perhaps most impressively,
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a, možda najimpresivnije je to što,
03:18
to calculate the density of our entire universe,
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pomoću njega proračunavaju gustinu čitavog univerzuma,
03:21
which, by the way,
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koji je inače,
03:23
still has infinitely less stuff in it
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i dalje sačinjen od beskrajno manje stvari
03:26
than the total number of digits in pi.
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u odnosu na ukupan niz cifara broja pi.
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