| 释义 |
contrafocal, a. Math.|kɒntrəˈfəʊkəl|
[contra- 2.]
Having, as two conics or conicoids, the sums of the squares of two corresponding axes equal: opposed to confocal conics, etc. in which the differences are equal.
1866Sylvester in Phil. Trans. 760 Contrafocal ellipsoids, the sums of whose squared axes are the same in all three directions. 1868E. J. Routh Rigid Dynamics 358 The momental ellipsoids of these bodies are contrafocal, i.e. have the sum of the squares of any two principal diameters the same in each ellipsoid.
Hence contrafocalism, the property of being contrafocal.
1866Sylvester in Phil. Trans. 771. |