Matrix: find element a23 of matrix A if A = ....

Makita

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Nov 16, 2006
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I am having trouble figuring out how to do problems that ask you to find a certain element within a matrix. For example:

Find element a23 of matrix A if A is the following:

. . .[ 2. .-3. ..4 ]
. . .[ 5. ..0. .-6 ]
. . .[ 7. ..2. .-8 ]

Could somebody tell me how to get started on these?
Thanks for any Help!

•Makita
 
\(\displaystyle A = \left[ {a_{j,k} } \right]_{n \times m} \quad j = 1,2 \cdots n\quad \& \quad k = 1,2 \cdots m.\)

Now the entry \(\displaystyle {a_{j,k} }\) appears in the j<SUP>th</SUP> row and k<SUP>th</SUP> column.
 
I don't understand your example. :( How does that apply to my question, could you maybe show me how yours translates to mine.

Sorry for my thick skull
•Makita
 
The term \(\displaystyle {a_{2,3} }\) is the number in the 2<SUP>nd</SUP> row and 3<SUP>rd</SUP> column of your matrix.
 
Ahhh, so the answer is -6. That was easy, it doesn't matter that it asks for element 23 and not 2, 3.
 
Makita said:
Ahhh, so the answer is -6. That was easy, it doesn't matter that it asks for element 23 and not 2, 3.
That is simply slopy notation.
 
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