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ERIC Number: EJ856226
Record Type: Journal
Publication Date: 2008-Mar
Pages: 9
Abstractor: As Provided
Reference Count: 0
ISBN: N/A
ISSN: ISSN-0746-8342
Fibonacci's Forgotten Number
Brown, Ezra; Brunson, Cornelius
College Mathematics Journal, v39 n2 p112-120 Mar 2008
Fibonacci's forgotten number is the sexagesimal number 1;22,7,42,33,4,40, which he described in 1225 as an approximation to the real root of x[superscript 3] + 2x[superscript 2] + 10x - 20. In decimal notation, this is 1.36880810785...and it is correct to nine decimal digits. Fibonacci did not reveal his method. How did he do it? There is also a curious mistake in his answer: why is it there? We first describe how Leonardo came to know this number. We then introduce several methods that he may have used for approximating roots of polynomials. Finally, we make a guess as to how he really did it.
Mathematical Association of America. 1529 Eighteenth Street NW, Washington, DC 20036. Tel: 800-741-9415; Tel: 202-387-5200; Fax: 202-387-1208; e-mail: maahq@maa.org; Web site: http://www.maa.org/pubs/cmj.html
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A