- Liu Hui
**Liu Hui**(zh-tsp|t=劉徽|s=刘徽|p=Liú Huī, fl.3rd century ) was a Chinesemathematician who lived in theWei Kingdom . In263 he edited and published a book with solutions to mathematical problems presented in the famous Chinese book of mathematics known as "The Nine Chapters on the Mathematical Art ".He was a descendant of Marquis of Zixiang of

Han dynasty , corresponding to now Zixiang township ofShandong province. He completed his commentary to the Nine Chapters in year 263.He probably visited Luoyang, and participted in measurements of sun shadow.**Mathematical work**Liu was one of the first mathematicians known to leave roots unevaluated, giving more exact results instead of approximations. Along with

Zu Chongzhi , they were among the greatest mathematicians of the ancient world.Needham, Volume 3, 85-86.] Liu Hui expressed all of his mathematical results in the form of decimal fractions (usingmetrological units), yet the laterYang Hui (c.1238 -1298 AD) expressed his mathematical results in full decimal expressions.Needham, Volume 3, 46.] Needham, Volume 3, 85.] He also provided commentary on the mathematical proof that is identical to thePythagorean theorem of the GreekPythagoras (c.580 BC -500 BC ).Needham, Volume 3, 22.] Liu Hui called the figure of the drawn diagram for the theorem the "diagram giving the relations between the hypotenuse and the sum and difference of the other two sides whereby one can find the unknown from the known".Needham, Volume 3, 95-96.] In terms of the treatment of plane areas and solid figures, Liu Hui was one of the greatest contributors to 'empirical ' solid geometry. For example, he figured out that a wedge with rectangular base and both sides sloping could be broken down into a pyramid and atetrahedral wedge.Needham, Volume 3, 98-99.] He also figured out that a wedge withtrapezoid base and both sides sloping could be made to give two tetrahedral wedges separated by a pyramid.In his commentaries on the

Jiuzhang suanshu , he presented (among other things):

*an algorithm for calculation of π in the comments to chapter 1.Needham, Volume 3, 66.] He calculated pi to $3.141024\; <\; pi\; <\; 3.142074$ with a 192 (= 2^{5}× 6) sidedpolygon . Archimedes used circumbscribed 96 polygon to obtain inequality $pi\; <\; frac\{22\}\{7\}$, and then used an inscribed 96-gon to obtain inequality $frac\{223\}\{71\}\; <\; pi$. Liu Hiu used only one inscribed 96-gon to obtain his π inequalily, and his results were a bit more accurate than Archimedes'.Needham, Volume 3, 100-101.] But he commented that 3.142074 was too large, and picked the first three digits of π=3.141024 ~3.14 and put it in fraction form $pi\; =\; frac\{157\}\{50\}$. He later invented a quick method and obtained $pi\; =3.1416$, which he doubled checked with 3072-gon(= 2^{9}× 6), he was quite happy about this result.Nine Chapters had used the value 3 for the π formula, but

Zhang Heng (78 -139 AD) had previously estimated it to the square root of 10;

*Gaussian elimination ;

*Cavalieri's principle to find the volume of a cylinder.Needham, Volume 3, 143.]The commentaries often include explanations why some methods work and why others do not. Although his commentary was a great contribution, some answers had slight errors which was later corrected by the Tang mathematician and Taoist believer

Li Chunfeng .Liu Hui also presented, in a separate appendix of 263 AD called "Haidao suanjing" or "

The Sea Island Mathematical Manual ", several problems related tosurveying . This book contained many practical problems of geometry, including the measurement of the heights ofChinese pagoda towers.Needham, Volume 3, 30.] This smaller work outlined instructions on how to measure distances and heights with "tall surveyor's poles and horizontal bars fixed at right angles to them".Needham, Volume 3, 31.] With this, the following cases are considered in his work:*The measurement of the height of an island opposed to its

sea level and viewed from the sea

*The height of a tree on a hill

*The size of a city wall viewed at a long distance

*The depth of aravine (using hence-forward cross-bars)

*The height of a tower on a plain seen from a hill

*The breadth of a river-mouth seen from a distance on land

*The depth of a transparent pool

*The width of a river as seen from a hill

*The size of a city seen from a mountain,Liu Hui's information about surveying was known to his contemporaries as well. The cartographer and state minister

Pei Xiu (224–271) outlined the advancements of cartography, surveying, and mathematics up until his time. This included the first use of a rectangular grid and graduated scale for accurate measurement of distances on representative terrain maps.Hsu, 90–96.]Liu Hui provided commentary on the Nine Chapter's problems involving the building of

canal and river dykes, giving results for total amount of materials used, the amount of labor needed, the amount of time needed for construction, etc.Needham, Volume 4, Part 3, 331.]Although translated into English long beforehand, Liu's work has been translated into French by Guo Shuchun, a professor from the

Chinese Academy of Sciences , who began this work in 1985 and took twenty years to complete it.**ee also***

Liu Hui's π algorithm

*The Sea Island Mathematical Manual

*History of mathematics

*History of geometry

*List of Chinese people

*History of China

*Chinese mathematics **Notes****References***Chen, Stephen. "Changing Faces: Unveiling a Masterpiece of Ancient Logical Thinking." "

South China Morning Post ", Sunday, January 28, 2007.

*Guo, Shuchun, [*http://203.72.198.245/web/Content.asp?ID=43261&Query=1 "Liu Hui"*] . "Encyclopedia of China " (Mathematics Edition), 1st ed.

*Hsu, Mei-ling. "The Qin Maps: A Clue to Later Chinese Cartographic Development," "Imago Mundi" (Volume 45, 1993): 90-100.

* Needham, Joseph & C. Cullen (Eds.) (1959). "Science and Civilisation in China: Volume III", section 19. Cambridge University Press. ISBN 0-521-05801-5.

*Needham, Joseph (1986). "Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth". Taipei: Caves Books, Ltd.

*Needham, Joseph (1986). "Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 3, Civil Engineering and Nautics". Taipei: Caves Books Ltd.

*Ho Peng Yoke: Liu Hui, Dictionary of Scientific Biography

*Yoshio Mikami: Development of Mathematics in China and Japan.

*Crossley, J.M et al, The Logic of Liu Hui and Euclid, Philosophy and History of Science, vol 3, No 1, 1994 this bo chen**External links*** [

*http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Liu_Hui.html Liu Hui at MacTutor*]

*Wikimedia Foundation.
2010.*

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**Liu Hui**— (chinesisch 劉徽; * um 220; † um 280) war ein chinesischer Mathematiker. Er lebte im Wei Reich. Liu Hui ist bekannt für seine Kommentare zu den Jiuzhang Suanshu, den Neun Büchern arithmetischer Technik. Dies ist eine Sammlung zur Lösung… … Deutsch Wikipedia**Liu Hui**— 劉徽 fue un matemático chino que vivió durante el Reinado de Wei. En el año 263 editó un libro que había sido compuesto en torno al inicio de nuestra era, conocido como Jiuzhang Suanshu o Los nueve capítulos del arte matemático, junto con… … Wikipedia Español**Liu Hui**— ▪ Chinese mathematician flourished c. 263 CE, China Chinese mathematician. All that is known about the life of Liu Hui is that he lived in the northern Wei kingdom (see Three Kingdoms) during the 3rd century CE. His fame rests on the… … Universalium**Liu Hui**— Dans ce nom chinois, le nom de famille, Liu, précède le prénom. Liu Hui (chinois : 刘徽 ; chinois traditionnel : 劉徽 ; hanyu pinyin : Liú Huī) était un mathématicien chinois qui vivait au IIIe siècle après J.C. En 263… … Wikipédia en Français**Liu Hui's π algorithm**— is a mathematical algorithm invented by Liu Hui (fl. 3rd century), a mathematician of Wei Kingdom. Before his time, the ratio of the circumference of a circle to diameter was often taken experimentally as 3 in China, while Zhang Heng (78… … Wikipedia**Liu Yao**— (劉曜) (d. 329), courtesy name Yongming (永明), was the final emperor of the Chinese/Xiongnu state Han Zhao. He became emperor in 318 after most other members of the imperial Liu clan were massacred by Jin Zhun in a coup. However, the empire was soon … Wikipedia**Liu**— ist ein chinesischer Familienname. Die Transkription Liu kann mit unterschiedlichen chinesischen Schriftzeichen ausgeführt werden, die Familiennamen 劉; (刘 in Kurzzeichen) (Lau auf kantonesisch), 柳, 留 sowie 六. Auf vietnamesisch kann der Name… … Deutsch Wikipedia**Liú**— Liu ist ein chinesischer Familienname. Die Transkription Liu kann mit unterschiedlichen chinesischen Schriftzeichen ausgeführt werden, die Familiennamen 劉; (刘 in Kurzzeichen) (Lau auf kantonesisch), 柳, 留 sowie 六. Auf vietnamesisch kann der Name… … Deutsch Wikipedia**Liu Yan (general)**— Liu Yan (Traditional Chinese: 劉縯; pinyin: Líu Yǎn) (d. 23), courtesy name Bosheng (伯升), was a general of one of the major uprisings against China s Xin Dynasty and its emperor, Wang Mang. Although he would have military successes, he would die… … Wikipedia**Liu Sheng**— (chinesisch 劉勝; † 113 v. Chr.) war ein Prinz der chinesischen Han Dynastie. Er war der siebte Sohn des Kaisers Jing, der von 157 bis 141 v. Chr. über China herrschte. Den Titel Prinz von Zhongshan erhielt er im Jahre 154 v. Chr. Seine… … Deutsch Wikipedia