## More Notation and Terminology

It's already been mentioned that the rectilinear coordinates of a complex
number in the complex plane are called the *real part* and
*imaginary part*, respectively.

We also have special notation and various names for the *polar
coordinates*
of a complex number :

The *complex conjugate* of is denoted
(or ) and is defined by

In general, you can always obtain the complex conjugate of any expression
by simply replacing with . In the complex plane, this is a *vertical flip* about the real axis; *i.e.*, complex conjugation
replaces each point in the complex plane by its *mirror image* on the
other side of the axis.

**Next Section:**

Elementary Relationships

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The Complex Plane