WOLFRAM|DEMONSTRATIONS PROJECT

The Trammel of Archimedes

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t
0
a
0.3
This Demonstration shows the construction of an ellipse using a rod fixed to two green points on the brown cross. As you elongate the ellipse, the size of the cross required changes accordingly. When the cross disappears (at
a=1
), the two green points coincide and a circle is produced.
The parametric equations for the ellipse are
x=asin(t)
,
y=cos(t).