Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

For differentiable matrix functions A,B:R→C n×n we have the product rule (AB)′ = AB′ + A′B . What is the difference to the case of plain functions?

share|improve this question

closed as not a real question by Jacob Black, copper.hat, Dominic Michaelis, Thomas, Cameron Buie Mar 4 '13 at 18:34

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

What has this got to do with the exponential? –  copper.hat Mar 4 '13 at 18:23
add comment

2 Answers 2

One big difference is that, for $n\geq 2$, you must watch and respect the order of the products.

Unlike with real valued functions where $$(fg)'=f'g+fg'=gf'+fg'=gf'+g'f=f'g+g'f.$$

share|improve this answer
+1 nice/leading hint. –  B. S. Mar 4 '13 at 18:26
add comment

No difference. ${}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}$

share|improve this answer
add comment

Not the answer you're looking for? Browse other questions tagged or ask your own question.