| 释义 |
spinode Geom.|ˈspaɪnəʊd|
[Irreg. f. L. spīna spine + node n.]
A stationary point on a curve; a cusp.
1852Cayley Math. Papers (1889) II. 28, I shall, with reference to plane curves,..use the term ‘node’ as synonymous with double point, and the term ‘spinode’ as synonymous with cusp. 1852G. Salmon Higher Plane Curves ii. (1879) 25 Such points are called cusps or spinodes. They are also called stationary points.
attrib.1852Cayley Math. Papers (1889) II. 29 The spinode-planes give rise to a developable which may be termed the ‘spinode-develope’. Also the ‘spinode-tangent’ is the tangent to the curve of intersection at the spinode. 1869Ibid. (1893) VI. 450 The spinode curve of the cubic surface. Ibid. 584 The spinode torse is the envelope of the parabolic planes of the surface. |