矢量
In mathematics, physics and engineering, a Euclidean vector or simply a vector (sometimes called a geometric vector or spatial vector) is a geometric object that has magnitude (or length) and direction. Vectors can be added to other vectors according to vector algebra. A Euclidean vector is frequently represented by a "ray" (a "directed line segment"), or graphically as an arrow connecting an "initial point" "A" with a "terminal point" "B", and denoted by formula_1 .