Introduction - If you have any usage issues, please Google them yourself
Catalog
A bit of basic arithmetic
1. the distance between two points on the plane is 1
2. determine whether the two points coincide 1
3. vector product 1
4. vector dot product 2
5. whether the judgment point is on the line 2
6. ask for a bit of the coordinates after a point of rotation 2
7. vector angle 2