| 释义 |
binode Geom.|ˈbaɪnəʊd|
[bi-2.]
A point on a surface at which there are two tangent planes.
1869Cayley in Phil. Trans. R. Soc. CLIX. 201 Conical and biplanar nodes, or, as I call them, cnicnodes, and binodes. 1874G. Salmon Analyt. Geom. (ed. 3) 457 The quadric cone may degenerate into a pair of planes. Such a node may be called a binode. 1934D. M. Y. Sommerville Anal. Geom. Three Dimensions xvii. 375 If the double-point at D is a binode, ax2 + {ddd} = 0 breaks up into two planes and the discriminant △ of this quadratic vanishes. |