# Inverse and identity matrix

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nur yusof on 22 Feb 2016
Commented: nur yusof on 23 Feb 2016
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 =
4 8 8
0 0 -8
0 0 4
The size of C matrix must be 6x3.But I only got 3x3. Why does it happen?

John D'Errico on 22 Feb 2016
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.
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nur yusof on 23 Feb 2016
Ok.Noted.Can you give me one example how to do it?

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