一理解基本概念1.零向量长度(或模)为0的向量称为零向量,记作0,0的方向是不定的,即它的方向是任意的,所以规定0与任意方向的向量平行.由于零向量的特殊性,故在解答有关向量的问题中,要注意题中是“零向量”,还是“非零向量”.2.单位向量长度(或模)等于一个单位长度的向量叫做单位向量.如,向量(AB|→)的单位向量为(?).又如,与一个非零 Understanding Basic Concepts 1. A vector whose zero vector length (or modulus) is 0 is called a zero vector. The direction of which is 0,0 is indefinite, that is, its direction is arbitrary. Therefore, 0 is specified to be parallel to the vector in any direction. Due to the special nature of the zero vector, in the question of solving the relevant vector, we must pay attention to whether the question is “zero vector” or “non-zero vector”. 2. The length of the unit vector (or modulus) is equal to a unit length vector is called A unit vector. For example, the unit vector of a vector (AB|→) is (?). Another example, with a non-zero