1 Because the direction of the 0 vector is arbitrary, the 0 vector is parallel to any vector.

2 For non-zero vector A, if there is a real number k that makes b=ka, then A is parallel to B..

It is the same concept that the vector is parallel to the vector * * * line, that is, the vector parallelism contains the same vector and the opposite vector.

4 2 parallel vectors A and B, satisfying: A curl b=0 vector.

5 a is parallel to b, and b is not a vector of 0, then there is a unique real number k, so a=kb.

6 2 Parallel vectors A and B satisfy: point A B = | A | | B | * COS (0) = | A | | B | or.

A point b = | a | *| b | * cos (π) =-| a | | | b |