Vectors   
                        =                    ||V|| =√(12²+(-5²))
Vectors are split into two values:

1. magnitude - the length of the vector 
2. direction - the direction of the vector 

magnitude is expressed as ||V||  - V stands for vector, so the magnitude of vector [12 -5] would be written ||12 -5||
magnitude =           ||V|| =√(a²+b²)
= V=√(12²+(-5²))