I Vector Diff. Q: Dot & Cross Prod. Differentiation?

sams
Gold Member
Messages
84
Reaction score
2
I have a question regarding the dot product and the cross product differentiation. I was wondering whether:
$$\frac{d(\vec{A}.\vec{B})}{du} = \vec{A}. \frac{d\vec{B}}{du} + \frac{d\vec{A}}{du} .\vec{B}$$
is the same as
$$\frac{d(\vec{A}.\vec{B})}{du} = \frac{d\vec{A}}{du} .\vec{B} + \vec{A}. \frac{d\vec{B}}{du}$$

and
$$\frac{d(\vec{A}×\vec{B})}{du} = \vec{A}× \frac{d\vec{B}}{du} + \frac{d\vec{A}}{du} ×\vec{B}$$
is the same as
$$\frac{d(\vec{A}×\vec{B})}{du} = \frac{d\vec{A}}{du} ×\vec{B} + \vec{A}× \frac{d\vec{B}}{du}$$

or not!

Thank you so much for your help...
 
Last edited:
Physics news on Phys.org
Addition is commutative even with vector elements, so yes, all equalities you wrote hold.
 
  • Like
Likes sams
DrClaude said:
Addition is commutative even with vector elements, so yes, all equalities you wrote hold.
Thank you DrClaude for your reply and for your help
 
Back
Top