The infinite life of pi - Reynaldo Lopes

1,578,864 views ・ 2013-07-10

TED-Ed


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Prevoditelj: Irma Komljenović Recezent: Ivan Stamenković
00:13
Try to measure a circle.
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Pokušaj izmjeriti krug.
00:15
The diameter and radius are easy,
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Promjer i polumjer je lagano izmjeriti,
00:17
they're just straight lines
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oni su samo ravne crte
00:18
you can measure with a ruler.
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koje možeš mjeriti ravnalom.
00:20
But to get the circumference,
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No da bi dobio opseg,
00:21
you'd need measuring tape or a piece of string,
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trebale bi ti traka za mjerenje ili djelić strune,
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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Pa, očito je
00:27
that a circle's circumference would get smaller or larger
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da bi se opseg kruga smanjivao ili povećavao
00:30
along with its diameter,
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s obzirom na promjer,
00:32
but the relationship goes further than that.
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no njihov odnos je dublji od toga.
00:34
In fact, the ratio between the two,
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Zapravo, omjer jednog i drugog,
00:36
the circumference divided by the diameter,
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opseg podijeljen s promjerom,
00:39
will always be the same number,
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uvijek će biti isti broj,
00:41
no matter how big or small the circle gets.
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bez obzira na to koliko je krug velik ili malen.
00:44
Historians aren't sure when or how
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Povjesničari nisu sigurni kada ili kako
00:46
this number was first discovered,
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je taj broj prvi put otkriven,
00:48
but it's been known in some form
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no poznat je u nekom obliku
00:50
for almost 4,000 years.
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već skoro 4,000 godina.
00:53
Estimates of it appear in the works of ancient Greek,
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Njegove procjene pojavljuju se u radovima drevnih grčkih,
00:55
Babylonian,
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babilonskih,
00:56
Chinese,
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kineskih
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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Čak se vjeruje da ga se koristilo
01:01
in building the Egyptian pyramids.
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u izgradnji egipatskih piramida.
01:03
Mathematicians estimated it
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Matematičari su ga procjenjivali
01:04
by inscribing polygons in circles.
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upisivanjem mnogokuta u krugove.
01:07
And by the year 1400,
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Do 1400. godine,
01:09
it had been calculated to as far as ten decimal places.
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izračunato je 10 njegovih decimala.
01:13
So, when did they finally figure out the exact value
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Pa, kada su napokon točno odredili njegovu vrijednost,
01:15
instead of just estimating?
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umjesto procjenjivanja?
01:17
Actually, never!
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Zapravo, nikad!
01:20
You see, the ratio
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Vidiš, omjer
01:21
of a circle's circumference to its diameter
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opsega kruga i njegova promjera
01:24
is what's known as an irrational number,
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iracionalan je broj,
01:26
one that can never be expressed
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što znači da ga se ne može izraziti
01:28
as a ratio of two whole numbers.
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kao omjer dvaju cijelih brojeva.
01:31
You can come close,
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Možeš biti blizu,
01:33
but no matter how precise the fraction is,
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no bez obzira na preciznost razlomka,
01:35
it will always be just a tiny bit off.
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uvijek će biti djelomično netočan.
01:38
So, to write it out in its decimal form,
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Da bi ga napisao u decimalnom obliku,
01:40
you'd have an on-going series of digits
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imao bi neprekidan niz znamenki
01:42
starting with
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počevši sa
01:43
3.14159
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3.14159
01:46
and continuing
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i nastavljajući se
01:47
forever!
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zauvijek!
01:49
That's why, instead of trying to write out
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Zato ga, umjesto da svaki put ispisujemo
01:51
an infinite number of digits every time,
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beskonačan broj znamenki,
01:53
we just refer to it using the Greek letter pi.
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jednostavno zovemo grčkim slovom pi.
01:57
Nowadays, we test the speed of computers
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Danas testiramo brzinu računala
01:59
by having them calculate pi,
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dajući im da računaju pi,
02:01
and quantum computers have been able
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a kvantna računala uspijevaju
02:03
to calculate it up to two quadrillion digits.
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izračunati i dvije bilijarde znamenki.
02:06
People even compete to see
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Ljudi se čak natječu
02:08
how many digits they can memorize
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u učenju znamenki napamet,
02:09
and have set records for remembering
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postavivši rekorde za
02:11
over 67,000 of them.
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više od 67,000 zapamćenih znamenki.
02:15
But for most scientific uses,
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No za većinu znanstvenih upotreba
02:16
you only need the first forty or so.
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trebaš prvih četrdesetak.
02:19
And what are these scientific uses?
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Koje su to znanstvene upotrebe?
02:21
Well, just about any calculations involving circles,
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Pa svaka u kojoj ima izračuna koji uključuju krugove,
02:25
from the volume of a can of soda
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od volumena limenke soka
02:27
to the orbits of satellites.
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do orbite satelita.
02:29
And it's not just circles, either.
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Ne radi se samo o krugovima.
02:30
Because it's also useful in studying curves,
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Zbog svoje primjene u proučavanju krivulja,
02:33
pi helps us understand periodic or oscillating systems
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pi nam pomaže shvatiti periodične ili oscilirajuće sustave
02:36
like clocks,
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kao što su satovi,
02:37
electromagnetic waves,
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elektromagnetski valova,
02:39
and even music.
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čak i glazba.
02:40
In statistics, pi is used in the equation
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U statistici pi se koristi u jednadžbi
02:43
to calculate the area under a normal distribution curve,
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za računanje površine ispod krivulje normalne raspodjele,
02:46
which comes in handy for figuring out distributions
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što pomaže u određivanju raspodjela
02:48
of standardized test scores,
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u rezultatima standardiziranih ispita,
02:50
financial models,
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financijskim modelima
02:51
or margins of error in scientific results.
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ili dopuštenoj pogreški u znanstvenim rezultatima.
02:54
As if that weren't enough,
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Kao da i to nije dovoljno,
02:55
pi is used in particle physics experiments,
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pi se koristi u pokusima fizike elementarnih čestica,
02:58
such as those using the Large Hadron Collider,
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poput onih u kojima se koristi veliki hadronski sudarač,
03:01
not only due to its round shape,
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ne samo zbog njegova okrugla oblika,
03:03
but more subtly,
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nego i suptilnije,
03:04
because of the orbits in which tiny particles move.
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zbog orbita u kojima se sitne čestice kreću.
03:07
Scientists have even used pi
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Znanstvenici su čak iskoristili pi
03:09
to prove the illusive notion
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da dokažu varljivu ideju
03:11
that light functions as both a particle
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da svjetlost funkcionira kao čestica
03:13
and an electromagnetic wave,
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i elektormagnetski val
03:16
and, perhaps most impressively,
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te, možda najimpresivnije,
03:18
to calculate the density of our entire universe,
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da izračunaju gustoću cijelog našeg svemira,
03:21
which, by the way,
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koji, usput,
03:23
still has infinitely less stuff in it
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ima beskonačno mnogo manje stvari u sebi
03:26
than the total number of digits in pi.
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nego ukupan broj znamenki pi.
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