### Phasor Notation

The complex amplitude
is also defined as the
*phasor* associated with any sinusoid having amplitude and
phase . The term ``phasor'' is more general than ``complex
amplitude'', however, because it also applies to the corresponding
*real* sinusoid given by the real part of Equations (1.9-1.10).
In other words, the real sinusoids
and
may be expressed as

and is the associated phasor in each case. Thus, we say that
the *phasor representation* of
is
. Phasor analysis is
often used to analyze linear time-invariant systems such as analog
electrical circuits.

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Complex Amplitude