Sujet : Re: How? ? ?
De : efji (at) *nospam* efi.efji (efji)
Groupes : sci.mathDate : 02. Apr 2025, 13:49:56
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Le 02/04/2025 à 14:32, Richard Hachel a écrit :
How can mathematicians come up with such absurdities?
https://www.youtube.com/watch?v=XZriBHTNPw0
No mathematician would write \sqrt{i} because the symbol "\sqrt" designs the positive square root of a real number, which does not make sense in \C since it is not an ordered set and the word "positive" is a nonsense in \C.
Anyway, "i" has 2 square roots : ±(1+i)/\sqrt{2}
and "-i" too : ±(1-i)/\sqrt{2}
Thus, the mathematically wrong expression "\sqrt{i}+\sqrt{-i}" is non univoque and could be any of these 4 values :
±\sqrt{2}, ±i\sqrt{2}
You're welcome
-- F.J.