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Re: [HM] Theorem of tangents
Posted:
Mar 28, 2001 4:57 PM


Francine F. Abeles wrote:
<< I'm interested in finding a reference in English to the origin and use of the theorem of tangents ..... >>
An elementary book in English that might be of your interest is Eli Maor's "Trigonometric Delights" [Princeton University Press, 1998.] See chapter xii, p. 152. This book is far from being a scholarly work, though Maor takes his job seriously.
"Around 1580 Viete stated a beautiful theorem that, unfortunately, has all but disappeared from today's textbooks: the Law of Tangents. . . . This theorem follows from the Law of Sines . . . but in Viete's time it was regarded as an independent theorem (3).
Note (3) [p. 162] ... As for other discoverers of the Law of Tangents, see David Eugene Smith, __History of Mathematics__ (1925, rpt. New York: Dover, 1958), vol. 2, pp. 611 and 631.

Fran, it goes without saying that _the_ reference (as far as secondary sources are concerned) for this kind of question is Braunmuehl's "Vorlesungen ueber Geschichte der Trigonometrie" (two volumes), published in Leipzig, B.G. Teubner, 190003.
Best wishes from excited Montevideo (UY soccer team is trying tonight to get back to its glorious and golden days),
Julio



