Wikipedia:Reference desk/Archives/Mathematics/2016 October 6

= October 6 =

Spherical Trigonometry
Can someone prove rigorous the spherical trigonometric identities/laws without using Linear algebra? יהודה שמחה ולדמן (talk) 12:37, 6 October 2016 (UTC)
 * Historically linear algebra is much later than spherical trigonometry, so the answer is yes. Bo Jacoby (talk) 16:31, 6 October 2016 (UTC).
 * OK, I'd like to see formal proofs for the Cosine rules and sine rules. יהודה שמחה ולדמן (talk) 17:50, 6 October 2016 (UTC)
 * Do you mean along the lines of Spherical law of cosines? Probably the 1886 Todhunter book has this. --Mark viking (talk) 20:57, 6 October 2016 (UTC)
 * I think we need a sketch review for this on that page. יהודה שמחה ולדמן (talk) 22:35, 6 October 2016 (UTC)