Question

why its important to write this in order ? ?
(u×v)'=u'×v+u×v'

Answer 1

because the cross product does not commute

Answer 2

ok and also this :O
(u.v)'=u'.v+u.v'

Answer 3

?

Answer 4

dot product commutes, so you can write it v dot u' + v' dot u

Answer 5

ok thanks !