Argand
# Jean Robert Argand

### Born: 18 July 1768
in Geneva, Switzerland

Died: 13 Aug 1822
in Paris, France

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**Argand** was an accountant who was only an amateur mathematician. He is famed for his geometrical interpretation of the complex numbers where **i** is interpreted as a rotation through 90.
The concept of the modulus of a complex number is due to him. He also gave a beautiful proof (with some gaps) of the fundamental theorem of algebra in 1814.

**References (2 books/articles)**

**A page from a work by Argand:**

A translation of a page of *Essai sur une manié,re de reprènter les quantitiés imaginaires dans les constructions gèomètriques * (1806)

**References elsewhere in this archive:**

Tell me about Argand's work on abstract linear spaces and on the fundamental theorem of algebra

There is a **Dorsa Argand** on the moon. You can see a list of lunar features named after mathematicians.

JOC/EFR December 1996