xA

yA

xB

xB-xA

yB-yA

yB

A = (2.5, 2)
B = (3.5, 3.5)
AB = Distance(A, B)
u = Vector(A, B)
B1: x(A)
B2: y(A)
B4: x(B)
B5: y(B)
B7: B4 - B1
B8: B5 - B2