Definition:Argand Diagram/Historical Note

Historical Note on Argand Diagram

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The Argand diagram appears in 's self-published $1806$ work Essai sur une manière de représenter les quantités imaginaires dans les constructions géométriques (Essay on a method of representing imaginary quantities).

This would have passed unnoticed by the mathematical community except that received a copy.

He had no idea who had published it (as had failed to include his name anywhere in it).

Legendre passed it to.

His brother found it in his papers after his death in $1810$, and published it in $1813$ in the journal Annales de mathématiques, announcing it as by an unknown mathematician.

He appealed for the author of the work to make himself known, which did, submitting a slightly modified version for publication, again in Annales de mathématiques.

By this time, however, had already himself invented the same concept.

It must be noted that this concept had in fact been invented by as early as $1787$, and been published in the paper Om directionens analytiske betegning by the Danish academy in $1799$.

This paper was rediscovered in $1895$ by, and later that year republished it.

's precedence is now universally recognised, but the term Argand Diagram has stuck.