HCRP project 2008

The original Conchoid of 280 BC

Conchoid of Nicomedes

Office: SciCtr 434

Email: knill@math.harvard.edu

Conchoids of Nicomedes are planar polar curves with r(t) = 1/cos(t) + c, where c
is a constant called offset. They are the images of a line under the exponential map of the
flat metric. These curves have great historical significance since they were used to tackle classical
problems in geometry like angle trisection or cube doubling, problems which can not be solved by
ruler and compass alone. One thinks that Conchoids were first used by Nicomedes in 200 BC to solve
the angle trisection problem. |

Questions and comments to knill@math.harvard.edu