Li Rui (; 8 December 1768 in

Suzhou Suzhou is a major prefecture-level city in southern Jiangsu province, China. As part of the Yangtze Delta megalopolis, it is a major economic center and focal point of trade and commerce. Founded in 514 BC, Suzhou rapidly grew in size by the ...

– 30 June 1817 in Suzhou) was a Chinese mathematician. Li discovered independently an equivalent version of what is known today as

Descartes' rule of signs In mathematics, Descartes' rule of signs, described by René Descartes in his ''La Géométrie'', counts the roots of a polynomial by examining sign changes in its coefficients. The number of positive real roots is at most the number of sign chang ...

References

*Joseph Warren Dauben and Christoph J. Scriba, eds., ''Writing the history of mathematics: its historical development'', Birkhäuser, 2002, p. 303. * {{DEFAULTSORT:Li, Rui 1768 births 1817 deaths Mathematicians from Jiangsu 18th-century Chinese mathematicians 19th-century Chinese mathematicians Historians of mathematics Scientists from Suzhou Qing dynasty people