A diagram on which complex numbers are represented geometrically using Cartesian axes, the horizontal coordinate representing the real part of the number and the vertical coordinate the complex part.‘Of course it is not unreasonable to call the geometrical interpretation of complex numbers the Argand diagram since it was Argand's work which was influential.’
- ‘We can plot a complex function on an Argand diagram, that is, a function whose values are complex numbers.’
- ‘In this paper he interpreted i as a rotation of the plane through 90 so giving rise to the Argand plane or Argand diagram as a geometrical representation of complex numbers.’
- ‘The Argand diagram is taught to most school children who are studying mathematics and Argand's name will live on in the history of mathematics through this important concept.’
Early 20th century named after J. R. Argand (1768–1822), French mathematician.