Cramer's rule for finding the inverse of an $n times n$ matrix

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Working off of this wikipedia article. I can understand all parts of the proof of cramer's rule, except for why $A_ij = 0$ for all $i neq j$, where $A_ij$ denotates the $i$th row and the $j$th column if the matrix $A$. I was wondering if anyone could explain to me why that must be the case. If this is something which ought to be self-evident please point me towards a video or article which could educate me on the principles I am missing.



EDIT: the part i do not follow is the last sentence of the second paragraph of the proof section of the aforementioned Wikipedia article.







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  • Can you point to the precise line or sentence where they use the statement which you don't follow? Skimming through the article I wasn't able to find what you're looking for.
    – Lukas Miristwhisky
    Aug 9 at 16:01










  • It is because there are two repeated columns.
    – user582578
    Aug 9 at 16:02










  • the part i do not follow is the last sentence of the second paragraph of the proof section.
    – dudester101
    Aug 9 at 21:45














up vote
0
down vote

favorite












Working off of this wikipedia article. I can understand all parts of the proof of cramer's rule, except for why $A_ij = 0$ for all $i neq j$, where $A_ij$ denotates the $i$th row and the $j$th column if the matrix $A$. I was wondering if anyone could explain to me why that must be the case. If this is something which ought to be self-evident please point me towards a video or article which could educate me on the principles I am missing.



EDIT: the part i do not follow is the last sentence of the second paragraph of the proof section of the aforementioned Wikipedia article.







share|cite|improve this question






















  • Can you point to the precise line or sentence where they use the statement which you don't follow? Skimming through the article I wasn't able to find what you're looking for.
    – Lukas Miristwhisky
    Aug 9 at 16:01










  • It is because there are two repeated columns.
    – user582578
    Aug 9 at 16:02










  • the part i do not follow is the last sentence of the second paragraph of the proof section.
    – dudester101
    Aug 9 at 21:45












up vote
0
down vote

favorite









up vote
0
down vote

favorite











Working off of this wikipedia article. I can understand all parts of the proof of cramer's rule, except for why $A_ij = 0$ for all $i neq j$, where $A_ij$ denotates the $i$th row and the $j$th column if the matrix $A$. I was wondering if anyone could explain to me why that must be the case. If this is something which ought to be self-evident please point me towards a video or article which could educate me on the principles I am missing.



EDIT: the part i do not follow is the last sentence of the second paragraph of the proof section of the aforementioned Wikipedia article.







share|cite|improve this question














Working off of this wikipedia article. I can understand all parts of the proof of cramer's rule, except for why $A_ij = 0$ for all $i neq j$, where $A_ij$ denotates the $i$th row and the $j$th column if the matrix $A$. I was wondering if anyone could explain to me why that must be the case. If this is something which ought to be self-evident please point me towards a video or article which could educate me on the principles I am missing.



EDIT: the part i do not follow is the last sentence of the second paragraph of the proof section of the aforementioned Wikipedia article.









share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Aug 9 at 21:44

























asked Aug 9 at 15:50









dudester101

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  • Can you point to the precise line or sentence where they use the statement which you don't follow? Skimming through the article I wasn't able to find what you're looking for.
    – Lukas Miristwhisky
    Aug 9 at 16:01










  • It is because there are two repeated columns.
    – user582578
    Aug 9 at 16:02










  • the part i do not follow is the last sentence of the second paragraph of the proof section.
    – dudester101
    Aug 9 at 21:45
















  • Can you point to the precise line or sentence where they use the statement which you don't follow? Skimming through the article I wasn't able to find what you're looking for.
    – Lukas Miristwhisky
    Aug 9 at 16:01










  • It is because there are two repeated columns.
    – user582578
    Aug 9 at 16:02










  • the part i do not follow is the last sentence of the second paragraph of the proof section.
    – dudester101
    Aug 9 at 21:45















Can you point to the precise line or sentence where they use the statement which you don't follow? Skimming through the article I wasn't able to find what you're looking for.
– Lukas Miristwhisky
Aug 9 at 16:01




Can you point to the precise line or sentence where they use the statement which you don't follow? Skimming through the article I wasn't able to find what you're looking for.
– Lukas Miristwhisky
Aug 9 at 16:01












It is because there are two repeated columns.
– user582578
Aug 9 at 16:02




It is because there are two repeated columns.
– user582578
Aug 9 at 16:02












the part i do not follow is the last sentence of the second paragraph of the proof section.
– dudester101
Aug 9 at 21:45




the part i do not follow is the last sentence of the second paragraph of the proof section.
– dudester101
Aug 9 at 21:45















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