Sum of two invertible matrices [duplicate]












0












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This question already has an answer here:




  • Product or sum of invertible matrix give an invertible matrix?

    3 answers




If A and B are two n x n invertible matrices, would the matrix result from A+B be invertible?



I think it would because for a matrix to be invertible its determinant would have to be greater than 0, and if you add the determinants of two matrices greater than 0 you would have to get a non zero answer. But is there any way to prove this?










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marked as duplicate by Dietrich Burde, Community Dec 19 '18 at 19:54


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.














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    $begingroup$
    1+(-1)=0$phantom{}$.
    $endgroup$
    – user1551
    Dec 19 '18 at 19:49
















0












$begingroup$



This question already has an answer here:




  • Product or sum of invertible matrix give an invertible matrix?

    3 answers




If A and B are two n x n invertible matrices, would the matrix result from A+B be invertible?



I think it would because for a matrix to be invertible its determinant would have to be greater than 0, and if you add the determinants of two matrices greater than 0 you would have to get a non zero answer. But is there any way to prove this?










share|cite|improve this question











$endgroup$



marked as duplicate by Dietrich Burde, Community Dec 19 '18 at 19:54


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.














  • 1




    $begingroup$
    1+(-1)=0$phantom{}$.
    $endgroup$
    – user1551
    Dec 19 '18 at 19:49














0












0








0





$begingroup$



This question already has an answer here:




  • Product or sum of invertible matrix give an invertible matrix?

    3 answers




If A and B are two n x n invertible matrices, would the matrix result from A+B be invertible?



I think it would because for a matrix to be invertible its determinant would have to be greater than 0, and if you add the determinants of two matrices greater than 0 you would have to get a non zero answer. But is there any way to prove this?










share|cite|improve this question











$endgroup$





This question already has an answer here:




  • Product or sum of invertible matrix give an invertible matrix?

    3 answers




If A and B are two n x n invertible matrices, would the matrix result from A+B be invertible?



I think it would because for a matrix to be invertible its determinant would have to be greater than 0, and if you add the determinants of two matrices greater than 0 you would have to get a non zero answer. But is there any way to prove this?





This question already has an answer here:




  • Product or sum of invertible matrix give an invertible matrix?

    3 answers








linear-algebra matrices






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edited Dec 19 '18 at 19:51









Bernard

123k741117




123k741117










asked Dec 19 '18 at 19:47









Finalsock23Finalsock23

11




11




marked as duplicate by Dietrich Burde, Community Dec 19 '18 at 19:54


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.









marked as duplicate by Dietrich Burde, Community Dec 19 '18 at 19:54


This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.










  • 1




    $begingroup$
    1+(-1)=0$phantom{}$.
    $endgroup$
    – user1551
    Dec 19 '18 at 19:49














  • 1




    $begingroup$
    1+(-1)=0$phantom{}$.
    $endgroup$
    – user1551
    Dec 19 '18 at 19:49








1




1




$begingroup$
1+(-1)=0$phantom{}$.
$endgroup$
– user1551
Dec 19 '18 at 19:49




$begingroup$
1+(-1)=0$phantom{}$.
$endgroup$
– user1551
Dec 19 '18 at 19:49










1 Answer
1






active

oldest

votes


















1












$begingroup$

The answer is generally no. For instance, consider
$$
A = pmatrix{1&0\0&1}, quad B = pmatrix{-1&0\0&-1}
$$






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$endgroup$













  • $begingroup$
    I see, thank you for your explanation!
    $endgroup$
    – Finalsock23
    Dec 19 '18 at 19:53


















1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









1












$begingroup$

The answer is generally no. For instance, consider
$$
A = pmatrix{1&0\0&1}, quad B = pmatrix{-1&0\0&-1}
$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    I see, thank you for your explanation!
    $endgroup$
    – Finalsock23
    Dec 19 '18 at 19:53
















1












$begingroup$

The answer is generally no. For instance, consider
$$
A = pmatrix{1&0\0&1}, quad B = pmatrix{-1&0\0&-1}
$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    I see, thank you for your explanation!
    $endgroup$
    – Finalsock23
    Dec 19 '18 at 19:53














1












1








1





$begingroup$

The answer is generally no. For instance, consider
$$
A = pmatrix{1&0\0&1}, quad B = pmatrix{-1&0\0&-1}
$$






share|cite|improve this answer









$endgroup$



The answer is generally no. For instance, consider
$$
A = pmatrix{1&0\0&1}, quad B = pmatrix{-1&0\0&-1}
$$







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Dec 19 '18 at 19:49









OmnomnomnomOmnomnomnom

129k792185




129k792185












  • $begingroup$
    I see, thank you for your explanation!
    $endgroup$
    – Finalsock23
    Dec 19 '18 at 19:53


















  • $begingroup$
    I see, thank you for your explanation!
    $endgroup$
    – Finalsock23
    Dec 19 '18 at 19:53
















$begingroup$
I see, thank you for your explanation!
$endgroup$
– Finalsock23
Dec 19 '18 at 19:53




$begingroup$
I see, thank you for your explanation!
$endgroup$
– Finalsock23
Dec 19 '18 at 19:53



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