In the USA we are taught at a young age that a ray is a line with one end, a compromise between a line and a line segment, something like $[0,\infty)$. Is there a word for this in french? I have talked to someone who is french and they did not know what a ray was.
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asked May 12, 2017 at 2:30
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1 Answer
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"On peut considérer aussi une portion de droite indéfinie dans un sens et limitée, dans l’autre, par un point. C’est ce que l’on nomme une demi-droite." Jacques Hadamard, Leçons de géométrie élémentaire, t.1, p.3 (1898). https://babel.hathitrust.org/cgi/pt?id=msu.31293001875347;view=1up;seq=10
answered May 12, 2017 at 2:48
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2$\begingroup$ My french is bad, is demidroite the answer? $\endgroup$ May 12, 2017 at 2:48
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$\begingroup$ Yes, demi-droite is the answer. Sorry. Droite is a line. $\endgroup$ May 12, 2017 at 2:49
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$\begingroup$ A small qualification: a ray of light is referred to as a "rayon" (see a French dictionary under this term). $\endgroup$ May 12, 2017 at 4:28
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$\begingroup$ I am not having anything to do with light though, I am asking for a mathematical context. $\endgroup$ May 17, 2017 at 2:34