دانشنامه ریاضی و کامپیوتر

Cruciform

A plane quartic curve also called the cross curve or policeman on point duty curve (Cundy and Rollett 1989). It is given by the implicit equation

(1)

which is equivalent to

(2)

and

(3)

In parametric form,

			(4)
			(5)

The curvature is given by

			(6)
			(7)

which, in the special case , reduces to

(8)

REFERENCES:

Cundy, H. and Rollett, A. Mathematical Models, 3rd ed. Stradbroke, England: Tarquin Pub., p. 71, 1989.

Lawrence, J. D. A Catalog of Special Plane Curves. New York: Dover, pp. 127 and 130-131, 1972.