## What is the Fibonacci sequence?

(Paradigm credit: belterz/Getty Images)

The Fibonacci sequence is a serial of numbers in which each number is the sum of the ii that precede it. Starting at 0 and ane, the sequence looks similar this: 0, ane, 1, 2, 3, 5, eight, 13, 21, 34, and so on forever. The Fibonacci sequence can be described using a mathematical equation: Xn+ii= Xn+ane + Xn

People claim in that location are many special properties nearly the numerical sequence, such as the fact that it is “nature’s secret code” for building perfect structures, like the

__Peachy Pyramid at Giza__

or the iconic seashell that likely graced the cover of your school

__mathematics__

textbook. But much of that is incorrect and the true history of the series is a bit more down-to-earth.

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Story backside Fibonacci sequence

The first thing to know is that the sequence is non originally Fibonacci’southward, who in fact never went by that name. The Italian mathematician who we telephone call Leonardo Fibonacci was born effectually 1170, and originally known as Leonardo of Pisa, said Keith Devlin, a mathematician at Stanford University.

Only in the 19th century did historians come up with the nickname Fibonacci (roughly meaning, “son of the Bonacci clan”), to distinguish the mathematician from another

__famous Leonardo of Pisa__, Devlin said.

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**Big Numbers that Define the Universe**Leonardo of Pisa did not actually discover the sequence, said Devlin, who is too the author of “Finding Fibonacci: The Quest to Rediscover the Forgotten Mathematical Genius Who Changed the Globe,” (Princeton Academy Press, 2017). Aboriginal Sanskrit texts that used

__the Hindu-Arabic numeral system__

first mention it in 200 B.C. predating Leonardo of Pisa by centuries.

“It’s been around forever,” Devlin told Live Science.

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Notwithstanding, in 1202 Leonardo of Pisa published the massive tome “Liber Abaci,” a mathematics “cookbook for how to practice calculations,” Devlin said. Written for tradesmen, “Liber Abaci” laid out Hindu-Arabic arithmetics useful for tracking profits, losses, remaining loan balances and so on, he added.

In one place in the book, Leonardo of Pisa introduces the sequence with a trouble involving__rabbits__. The trouble goes equally follows: Start with a male and a female rabbit. After a calendar month, they mature and produce a litter with some other male and female rabbit. A month afterwards, those rabbits reproduce and out comes — you guessed it — another male person and female, who likewise can mate later on a calendar month. (Ignore the wildly improbable biological science here.) After a year, how many rabbits would you have?

The respond, information technology turns out, is 144 — and the formula used to get to that answer is what’s now known as the Fibonacci sequence.

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**9 equations that changed the earth**“Liber Abaci” first introduced the sequence to the Western globe. Merely after a few scant paragraphs on convenance rabbits, Leonardo of Pisa never mentioned the sequence again. In fact, it was mostly forgotten until the 19th century, when mathematicians worked out more most the sequence’s mathematical properties. In 1877, French mathematician Édouard Lucas officially named the rabbit trouble “the Fibonacci sequence,” Devlin said.

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Why is the Fibonacci sequence pregnant?

Other than existence a swell teaching tool, the Fibonacci sequence shows up in a few places in nature. However, it’s non some secret lawmaking that governs the architecture of the universe, Devlin said.

It’s truthful that the Fibonacci sequence is tightly connected to what’s now known as__the aureate ratio, phi__, an

__irrational number__

that has a great bargain of its ain dubious lore. The ratio of successive numbers in the Fibonacci sequence gets ever closer to the gilded ratio, which is 1.6180339887498948482…

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**The 9 most massive numbers in being**The golden ratio manages to capture some types of establish growth, Devlin said. For instance, the spiral arrangement of leaves or petals on some plants follows the gilt ratio. Pinecones showroom a golden spiral, as do the seeds in a sunflower, according to “__Phyllotaxis: A Systemic Study in Found Morphogenesis__

(opens in new tab)” (Cambridge University Press, 1994). But there are just as many plants that practice not follow this dominion.

“It’s non ‘God’s only rule’ for growing things, permit’south put it that mode,” Devlin said.

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The seashell and ‘Vitruvian Man’

Perhaps the well-nigh famous example of all, the seashell known as the nautilus, does non in fact grow new cells according to the Fibonacci sequence, he added. When people offset to draw connections to the

__human body__, art and architecture, links to the Fibonacci sequence get from tenuous to downright fictional.

“It would take a big volume to document all the misinformation well-nigh the golden ratio, much of which is simply the repetition of the same errors by different authors,” George Markowsky, a mathematician who was then at the University of Maine,

__wrote in a 1992 newspaper__

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in the College Mathematics Journal.

Much of this misinformation tin can be attributed to an 1855 book by the German psychologist Adolf Zeising called “Aesthetic Research.” Zeising claimed the proportions of the human trunk were based on the gilded ratio. In subsequent years, the gilded ratio sprouted “golden rectangles,” “aureate triangles” and all sorts of theories about where these iconic dimensions ingather up.

Since then, people have said the golden ratio can be found in the dimensions of the Pyramid at Giza, the Parthenon,__Leonardo da Vinci__‘due south “Vitruvian Man” and a bevy of Renaissance buildings. Overarching claims about the ratio being “uniquely pleasing” to the human being eye have been stated uncritically, Devlin said. All these claims, when they’re tested, are measurably false, he added.

“We’re good pattern recognizers. Nosotros can encounter a pattern regardless of whether it’s at that place or not,” Devlin said. “It’due south all just wishful thinking.”

*Editor’southward note: Adam Mann contributed to this article*.

*Originally published on Live Scientific discipline*.

**Source: https://www.livescience.com/37470-fibonacci-sequence.html**