Editing Locus (mathematics) (section)

===Third example===
[[File:Geassocieerde rechten.svg|thumb|The intersection point of the associated lines ''k'' and ''l'' describes the circle]]
A locus can also be defined by two associated curves depending on one common [[parameter]]. If the parameter varies, the intersection points of the associated curves describe the locus.

In the figure, the points ''K'' and ''L'' are fixed points on a given line ''m''. The line ''k'' is a variable line through ''K''. The line ''l'' through ''L'' is [[perpendicular]] to ''k''. The angle <math>\alpha</math> between ''k'' and ''m'' is the parameter.
''k'' and  ''l'' are  associated lines depending on the common parameter. The variable intersection point ''S'' of ''k'' and ''l'' describes a circle. This circle is the locus of the intersection point of the two associated lines.