Reason: Print letters (such as A, B, U, V) in bold, and add a small arrow "→" at the top of the letter when writing. If the starting point (a) and the ending point (b) of the vector are given, the vector can be recorded as AB (and added to the top →). In the space Cartesian coordinate system, vectors can also be expressed in pairs. For example, (2,3) in the xOy plane is a vector.

Extended data:

1, Vector Algebra Representation:

Generally speaking, printed letters (a, b, c, etc. ) is bold, and handwritten letters are indicated by arrows (→) after a, b, c, etc.

2, geometric representation:

A vector can be represented as a directed line segment. The length of the directed line segment is equal to the size of the vector, and the size of the vector is also the length of the vector. A vector with a length of 0 is called a zero vector. We call it a vector with a length equal to 1 unit, and we call it a unit vector.

Baidu Encyclopedia-Vector