Subtracting Points
No, I'm not talking about your midterm

The previous formula for calculating a displacement vector (click here to review it) can be written as:

Displacement from point S (start) to point F (finish) =

F - S = ( Xf , Yf )T - ( Xs , Ys )T = ( Xf-Xs , Yf-Ys )T

In this operation two points are used to produce one vector:

Don't skip over this observation with a yawn. Think a few careful thoughts now to avoid confusion later on. It is slightly odd that a "minus" with two objects of one type produces an object of another type.