Tangent of the Cross Curve

Also known as the Cruciform

x = a sec t

y = b csc t

The cross curve was first conceived by Terquem in 1847.

References:     R.C. Yates, Curves and Their Properties, p. 203.
                          J. Dennis Lawrence, A Catalog of Special Plane Curves, pp. 130-131.
                          蔣聲, 形形色色的曲線, pp. 120-121.