cubic (kubik)

and n. [= F. cubique = Sp. cúbico = Pg. It. cubico, 3. In alg. and geom., being of the third order, degree, or power. - Cubic alum. See alum. - Cubic curve. See curve. Cubic or cubical determinant. See determinant. - Cubic elliptois, a curve whose equation is ay3 = x2(b-x). It is a cuspidal cubic tangent to the line at infinity. - Cubic equation, in alg., an equation in which the highest power of the unknown quantity is a cube. Cubic number, cubic quantity. Same as cube, 2.- Cubic surface, a surface whose point-equation is of the third degree; a surface cut by every line in space in three points, real or imaginary. - Cubic system, in crystal., same isometric system. See crystallography. Plane cubic parabola, a cubic of the form a2x =y3. It is a cubic of the third cla , having a cusp at infinity and a single point of inflection (which is a center). - Twisted cubic curve. See twisted cubic, below. II. n. In math ., a cubical quantic, equation, or curve. - Binary, ternary, quaternary cubic, a homogeneous entire function of the third degree, containing two, three, or four variables. - Characteristic of a cubic. See characteristic.- Circular cubic, cuspidal cubic. See the adjectives. - Twisted cubic, a curve in space which is cut by every plane in three points, real or imaginary.