Al Kashi

The law of cosines is in France also called Al Kashi theorem. Here are some links to this mathematician the law of cosines: Wikipedia Al Kashi Wikiipedia Mac Tutor Al Kashi 1380-1429 In my copy of "Katz" book, I did not find the claim substantiated that Al Kashi had proven a version of the cos theorem but I keep looking for sources. Here are scans of that book showing the relevant pages on Al Kashi:

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Maths21A | Oliver Knill | Summer 2009 | Summer school | Department of Mathematics | Faculty of Art and Sciences | Harvard University QR code of this page