科學史：非歐幾何到底是什麼？讓數學家吵了2000年！

三角形內角和，這個兩小學生都知道的問題，卻困惑了數學家近兩千年！為什麼三角形內角和不等於180度！究竟奇葩的非歐幾何是什麼？！

https://www.zhihu.com/video/970265378002284544

參考資料

https://en.wikipedia.org/wiki/Non-Euclidean_geometry

https://en.wikipedia.org/wiki/Carl_Friedrich_Gauss

https://en.wikipedia.org/wiki/Nikolai_Lobachevsky

https://en.wikipedia.org/wiki/Elliptic_geometry

https://en.wikipedia.org/wiki/Hyperbolic_geometry

http://www-groups.dcs.st-and.ac.uk/history/HistTopics/Non-Euclidean_geometry.html

http://web.colby.edu/thegeometricviewpoint/2016/12/08/history-of-hyperbolic-geometry/

https://en.wikipedia.org/wiki/Riemannian_geometry

https://en.wikipedia.org/wiki/Bernhard_Riemann

https://en.wikipedia.org/wiki/Eudoxus_of_Cnidus

https://en.wikipedia.org/wiki/Pythagoreanism

https://en.wikipedia.org/wiki/Thales_of_Miletus

https://en.wikipedia.org/wiki/Klein_bottle

https://en.wikipedia.org/wiki/Geometry#See_also

https://www.britannica.com/science/non-Euclidean-geometry

https://www.britannica.com/science/geometry#ref217502

https://files.eric.ed.gov/fulltext/EJ717835.pdf