Cabri Java Applet Illustrating the Osculating Circle of the Conchoid of Necomedes Osculating Circle of the Conchoid of Nicomedes r = a + sec t References: J. Dennis Lawrence, A Catalog of Special Plane Curves, pp. 137-138. 蔣聲, 形形色色的曲線, pp. 99-101. E. H. Lockwood, A Book of Curves, pp. 127-129. R.C. Yates, Curves and Their Properties, pp. 31-33.