Lemniscate of Gerono

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The lemniscate of Gerono

In algebraic geometry, the lemniscate of Gerono, or lemniscate of Huygens, or figure-eight curve, is a plane algebraic curve of degree four and genus zero and is a lemniscate curve shaped like an symbol, or figure eight. It has equation

It was studied by Camille-Christophe Gerono.


Because the curve is of genus zero, it can be parametrized by rational functions; one means of doing that is

Another representation is

which reveals that this lemniscate is a special case of a Lissajous figure.

Dual curve[edit]

The dual curve (see Plücker formula), pictured below, has therefore a somewhat different character. Its equation is

Dual to the lemniscate of Gerono


  • J. Dennis Lawrence (1972). A catalog of special plane curves. Dover Publications. p. 124. ISBN 0-486-60288-5.

External links[edit]