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Clarence
 one year ago
I don't understand this question.
Calculate the second term in the cofactor expansion along the third row for the matrix:
[[1,1,1,1],[1,1,2,0],[1,1,0,2],[1,1,1,1]]
Clarence
 one year ago
I don't understand this question. Calculate the second term in the cofactor expansion along the third row for the matrix: [[1,1,1,1],[1,1,2,0],[1,1,0,2],[1,1,1,1]]

This Question is Closed

clarence
 one year ago
Best ResponseYou've already chosen the best response.1\[\left[\begin{matrix}1 & 1 & 1 & 1 \\ 1 & 1 & 2 & 0 \\ 1 & 1 & 0 & 2 \\ 1 & 1 & 1 & 1\end{matrix}\right]\]

clarence
 one year ago
Best ResponseYou've already chosen the best response.1So the third row would be [1, 1, 0, 2]

clarence
 one year ago
Best ResponseYou've already chosen the best response.1So do I just use 1 times the rest of the matrix?

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3\[\left[\begin{matrix}1 & 1 & 1 & 1 \\ 1 & 1 & 2 & 0 \\ 1 & \color{red}{1} & 0 & 2 \\ 1 & 1 & 1 & 1\end{matrix}\right]\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I guess you can take the determinant?

clarence
 one year ago
Best ResponseYou've already chosen the best response.1Take the determinant of the original matrix and times that by 1?

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3whats the definition of "term" that your professor uses ?

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3does the determinant has \(4!=24\) terms or just \(4\) terms according to your prof ?

clarence
 one year ago
Best ResponseYou've already chosen the best response.1I think she'd say that that'd be just 4 terms.

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3** then, you just need to find the cofactor of 1, which is at 3,2 location, then multiply that by 1

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3** cofactor of \(A_{32}\)= \((1)^{3+2}\begin{vmatrix}1&1&1\\1&2&0\\1&1&1\end{vmatrix}\)

clarence
 one year ago
Best ResponseYou've already chosen the best response.1Okay, I am obviously not understanding this question because the answer I got was 0...

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3Right, I think your prof wants the first term out of those 24 terms in the determinant

clarence
 one year ago
Best ResponseYou've already chosen the best response.1There's a similar question on this website that went unanswered: http://openstudy.com/study#/updates/5039e2afe4b043c156a3277c

clarence
 one year ago
Best ResponseYou've already chosen the best response.1How did they obtain 20 in this example? https://au.answers.yahoo.com/question/index?qid=20120826032029AANjdNA

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3the answer is either 0 or 2 0 if you consider 4 terms in the determinant 2 if you consider 24 terms

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3yahoo answers is not that reliable..

clarence
 one year ago
Best ResponseYou've already chosen the best response.1Aha, I know, I was just trying to work out how they managed to get 20 that's all

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3they got 40 right ?

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3remember how to find cofactor of a term ?

clarence
 one year ago
Best ResponseYou've already chosen the best response.1Yes, but it's a bit hard to write it all on here.

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3[3,1,2,1] [2,2,1,2] [2,2,2,1] [1,3,2,1] to find the cofactor of 2 at position 3,2 you simply find the determinant of the small matrix obtained by deleting 3rd row and second column, then fix the sign

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3removing 3rd row and 2nd column, [3,2,1] [2,1,2] [1,2,1]

clarence
 one year ago
Best ResponseYou've already chosen the best response.1And then multiplying all that by 2.

clarence
 one year ago
Best ResponseYou've already chosen the best response.1What I don't understand is how they ended up getting (2) x (20) to get 40.

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3before that, multiply the determinant by \((1)^{3+2}\) to get the cofactor

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3what do you get for determinant of [3,2,1] [2,1,2] [1,2,1]

clarence
 one year ago
Best ResponseYou've already chosen the best response.1So for my particular question, the determinant of the submatrix is just 0, does this mean that the answer is just 0 then?

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3let me just quote my previous reply ``` the answer is either 0 or 2 0 if you consider 4 terms in the determinant 2 if you consider 24 terms ```

clarence
 one year ago
Best ResponseYou've already chosen the best response.1Yeah, I remember reading that, I was just confused as to how you managed to get 2 as well if I considered 24 terms rather than 4

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3lets work it step by step

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3how many terms are there in the determinant of a 2x2 matrix ?

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3\[ \begin{vmatrix}a&b\\c&d\\\end{vmatrix} = adbc\] two terms, right ?

ganeshie8
 one year ago
Best ResponseYou've already chosen the best response.3how about the determinant of a \(3\times 3\) matrix, how many terms ?
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