Complex conjugate

Revision as of 21:20, 1 January 2008 by Pengm14 (talk | contribs) (Properties)

The complex conjugate of a complex number $z = a + bi$ is the complex number $\overline{z} = a - bi$.

Geometrically, if $z$ is a point in the complex plane, $\overline z$ is the reflection of $z$ across the real axis.

Properties

Conjugation is its own functional inverse and commutes with the usual operations on complex numbers:

  • $\overline{(\overline z)} = z$.
  • $\overline{(w \cdot z)} = \overline{w} \cdot \overline{z}$. ($\overline{(\frac{w}{z})}$ is the same as $\overline{(w \cdot \frac{1}{z})}$)
  • $\overline{(w + z)} = \overline{w} + \overline{z}$. ($\overline{(w - z)}$ is the same as $\overline{(w + (-z))}$)

It also interacts in simple ways with other operations on $\mathbb{C}$:


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