To I know some math...so what is your point? Sorry but confusing.?

Question

Even if

(AB)T=BTAT

since on the RHS is 0

Isn't it just the same

Answer 1

Here's the proof you need

Let
A be p x r
B be r x q

Thus
AB is p x q by matrix multiplication,
and (AB)^T is q x p
where A^T is r x p
and B^T is q x r
by definition.

Equality of corresponding entries is proven hereinafter:
For
1 <= i <= q
1 <= j <= p

Then by definition
<(AB)^T>_ij = _ji
= [Summation from k = 1 to r of { _jk _ki } ]
= [Summation from k = 1 to r of { _ik _kj} ]
= _ij

Hence the (i, j) entries of (AB)^T and B^T A^T are equal.

This proves that (AB)^T = B^T A^T

which in your notation (AB)T = BTAT

thus ends this proof

q.e.d.


I just realized that you were writing to the person "I know some math" from your other question. I guess you didn't really need this proof. Looking at other question it is obvious that you didn't need this property since you didn't even multiply!!!!
Transpose on addition is distrubitve. So you were correct in your proof, so ignore what "I know some math" said.

Answer 2

Hey, Mickey, you need to ask this question back at your old question. No one knows what you are talking about. I went back and looked at your last question and I know what you are talking about. Click on your avatar box, that face on the left of your question above. The page that comes up is your Question and Answer page. Scroll down, click on your question that you asked before this one. When that question page comes up, see the toolbar under that question. On right of tool bar is little pencil. Click that pencil. Then click "add details". Write in the box any added details you want to make to "I Know Some Math", click "submit" and it will show up under that question. Anytime that you want to add details again, even more than once, just click on the pencil icon under the question. Good luck.

Mickey, also, you can click on his avatar, the face in the box next to his answer back at your old question. His Q&A page will open. In upper left there will be a link to e-mail him directly.

Answer 3

Please include a link to the post from "I know some math" so that the rest of us can follow. Thanks!

Answer 4

What is your question or point??