ERIC Number: EJ769591
Record Type: Journal
Publication Date: 2006
Pages: 4
Abstractor: ERIC
Reference Count: 3
ISBN: N/A
ISSN: ISSN-0730-8639
An Arctangent Triangle: Puzzling over Arctan1 + Arctan2 + Arctan3 = [pi]
Ecker, Michael W.
Mathematics and Computer Education, v40 n2 p124-127 Spr 2006
The author has always been fascinated by the title identity. It's charming and simple, as well as easy to believe after pressing a few calculator keys. Several fine proofs have appeared in the literature, including several proofs without words. His own earlier proof is trigonometric, and he has often been dissatisfied with not being able to produce his own simple, direct, purely geometric proof. In this paper, the author offers both trigonometric and geometric proofs of Arctan1 + Arctan2 + Arctan3 = [pi], as well as a unifying puzzle.
Descriptors: Geometric Concepts, Geometry, Trigonometry, Problem Solving, Mathematics, Mathematical Logic, Validity
MATYC Journal Inc. Mathematics and Computer Education, P.O. Box 158, Old Bethpage, NY 11804. Tel: 516-822-5475; Web site: http://www.macejournal.org
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Identifiers: N/A

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