---
tag: 070PFSYJJR
kind: concept
name: Argument of a complex number
aliases: [angle-of-a-complex-number]
msc: [30A99]
sources:
  - url: https://en.wikipedia.org/wiki/Argument_(complex_analysis)
    locator: lead section
same_as:
  wikidata: Q1780131
  wikipedia: Argument (complex analysis)
---

## Summary

The argument of a nonzero complex number $z$ is the angle from the positive real axis to $z$ in the [[complex plane|0CTE7A31XQ]].
It is determined up to a multiple of $2\pi$.
The usual choice in $(-\pi, \pi]$ is the [[principal value|0SQSQP748R]].