A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 4 years ago
I need to prove that if a and b are 3x3 diagonal matrices, than ab=ba. I have proved it, but I just made up two diagonal matrices and multiplied them together, to show that ab=ba. Is there a more mathematical way to prove this, or is this proof sufficient?
anonymous
 4 years ago
I need to prove that if a and b are 3x3 diagonal matrices, than ab=ba. I have proved it, but I just made up two diagonal matrices and multiplied them together, to show that ab=ba. Is there a more mathematical way to prove this, or is this proof sufficient?

This Question is Closed

UnkleRhaukus
 4 years ago
Best ResponseYou've already chosen the best response.0if the matrices you used some how include all possible matrices then it has been proved, ie used matrices with letters for elements

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0That is what I did. I got that both ab and ba =dw:1328657180796:dw so, that is enough proof?

phi
 4 years ago
Best ResponseYou've already chosen the best response.1looks ok. you could also use the fact that for diagonal matrix A \[ A^T = A \] and the general property \[ (AB)^T= B^TA^T=BA \]

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0ah, so what your saying is that for any nxn matrix, ^^ hols true, and since 3x3 is an nxn, then that also holds true. Thanks!
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.