«Science History»
Xiahou Yang

Xiahou Yang

Born: about 400 in China
Died: about 470 in China

Xiahou Yang is also known as Hsiahou Yang. Nothing is known of Xiahou Yang except as the supposed author of the Xiahou Yang suanjing (Xiahou Yang's Mathematical Manual). However, according to [3], there is no doubt that the Xiahou Yang suanjing was not written by Xiahou Yang. What then do the dates we give for his life mean? What we have done is to use the best available evidence for the dates when the Xiahou Yang suanjing was written and deduce approximate dates for Xiahou Yang from that. If that seems somewhat perverse, given that it seems almost certain that Xiahou Yang did not write the work, then we can only plead weakly that we have no other option!

The dating of the work is fairly well pinned down. We have comments by Zhang Qiujian which criticise the accuracy of one of the solutions given in the Xiahou Yang suanjing (Xiahou Yang's Mathematical Manual). This gives 468 as the latest possible date for the work to be written. On the other hand a change of volume standard which took place in 425 in mentioned in the text so it must have been written after that date. The dates we give cannot therefore be more than 40 years in error for the author of the work.

The treatise contains three chapters in the usual style of problems and solutions. Chapter 1 contains 19 problems, chapter 2 contains 29 problems and the final chapter contains 44 problems. One significant idea which appears in the text concerns representation of numbers in the decimal notation. Xiahou Yang notes that to multiply a number by 10, 100, 1000, or 10000 all that needs to be done is that the rods on the counting board are moved forwards by 1, 2, 3, or 4 decimal places. Similarly to divide by 10, 100, 1000, or 10000 the rods are moved backwards by 1, 2, 3, or 4 decimal places. What is significant here is that Xiahou Yang seems to understand not only positive powers of 10 but also decimal fractions as negative powers of 10.

Although Xiahou Yang has no symbol for 0 in an empty place, there is good evidence from his description of moving numbers to the right and left that he at least has a virtual zero in mind despite the lack of a symbol.

Certainly when Li Chunfeng came to edit this text to make it a suitable text for the Imperial examinations, which it became in 656, he had to correct some of the problems. In particular some of the problems dealing with areas in the Xiahou Yang suanjing (Xiahou Yang's Mathematical Manual) use incorrect formulae.

Article by: J J O'Connor and E F Robertson

December 2003
MacTutor History of Mathematics
Search All Ebay* AU* AT* BE* CA* FR* DE* IN* IE* IT* MY* NL* PL* SG* ES* CH* UK*
KJV Holy Bible King James Version Black Giant Print Thumb Indexing Faux Leather

End Date: Saturday Jul-14-2018 10:39:53 PDT
Buy It Now for only: $24.99
About My Mother... By Peggy Rowe

End Date: Friday Jun-29-2018 14:14:56 PDT
Buy It Now for only: $12.22
F.U. Money: Make as Much Money as You Damn Well Want and Live Your Life as You D

End Date: Wednesday Jun-20-2018 16:21:39 PDT
Buy It Now for only: $27.23
The Cannabis Grow Bible: The Definitive Guide to Growing Marijuana for Recreatio

End Date: Sunday Jul-15-2018 16:14:56 PDT
Buy It Now for only: $9.00
Bestseller Paperback Copy of The 5 Love Languages: The Secret to Love that Lasts

End Date: Sunday Jul-1-2018 13:08:07 PDT
Buy It Now for only: $4.50
It Is Well with My Soul Adult Coloring Book (Coloring Faith)

End Date: Wednesday Jul-4-2018 23:43:04 PDT
Buy It Now for only: $11.97
Think and Grow Rich by Napoleon Hill (2012, Hardcover)

End Date: Wednesday Jun-20-2018 0:25:04 PDT
Buy It Now for only: $8.00
Born A Crime: Stories from a South African Childhood by Trevor Noah (Brand New)

End Date: Friday Jul-13-2018 12:49:33 PDT
Buy It Now for only: $14.00

Great hera! Check out our Wonder Woman merch here!

Start: 17 Jul 2017 | End: 31 Jan 2018

Enjoy 10% OFF with coupon: SHOPTD5, offer valid until 04/30/2018.


Start: 29 Oct 2017 | End: 30 Apr 2018

Save $75 on flight+hotel booking with code: VACAY75

Code: VACAY75

Start: 21 Sep 2017 | End: 01 Apr 2018

Search All Amazon* UK* DE* FR* JP* CA* CN* IT* ES* IN* BR* MX
Booking.com B.V. is based in Amsterdam in the Netherlands. Ready for some statistics? Our 1,534,024 properties, including 860,482 holiday rentals, are located in 123,105 destinations in 229 countries and territories, and are supported internationally by 198 offices in 70 countries.
2013 Copyright © Techhap.com Mobile version 2015 | PeterLife & company
Skimlinks helps publishers monetize editorial content through automated affiliate links for products.
Terms of use Link at is mandatory if site materials are using fully or particulary.
Were treated to the site administrator, a cup of coffee *https://paypal.me/peterlife