January 2001

y = 2 cos(t)^{2}

-1.1 <= t <= 1.1

Parametrisation of x^{2} y = 4 (2 - y)

Studied in 1748 by Maria Gaetana Agnesi and earlier by Fermat around 1666 and Grandi in 1703. Agnesi called the curve "versiera".