Editing Parameter (section)

===Analytic geometry===
{{Main|Parametric equation|Parametrization (geometry)}}

In [[analytic geometry]], a [[curve]] can be described as the image of a function whose argument, typically called the ''parameter'', lies in a [[interval (mathematics)|real interval]].

For example, the [[unit circle]] can be specified in the following two ways:

* ''implicit'' form, the curve is the locus of points {{math|(''x'', ''y'')}} in the [[Cartesian coordinate system|Cartesian plane]] that satisfy the relation <math display=block>
x^2 + y^2 = 1.
</math>
* ''parametric'' form, the curve is the image of the function <math display=block>
t \mapsto (\cos t, \sin t)
</math><p>with parameter <math>t \in [0, 2\pi).</math> As a [[parametric equation]] this can be written</p><math display=block>
(x,y)=(\cos t,\sin t).
</math><p>The parameter {{mvar|t}} in this equation would elsewhere in mathematics be called the ''[[independent variable]]''.</p>