Inverse and identity matrix

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nur yusof 2016-2-22

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/269401-inverse-and-identity-matrix

评论： nur yusof 2016-2-23

采纳的回答： John D'Errico

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Given. A=[1 2 3;6 7 8;11 12 13]; B=[4 5 6;9 10 11;14 15 16]; and C=-inv(A)*B/eye(3). And the C matrix is

C =

   8     8
   0    -8
   0     4

The size of C matrix must be 6x3.But I only got 3x3. Why does it happen?

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Answer 1

John D'Errico 2016-2-22

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It happens because of the basic rules of those matrix operators.

All of your matrices are 3x3. Both of those binary operations (* and /) between 3x3 matrices result in another 3x3 matrix.

My guess is you have invented in your mind a new rule for the / operator, wherein it becomes a matrix concatenation operator, or something like that. Sorry, but operators have explicit definitions in MATLAB. They follow their defined behaviors, as I would hope they should.