- #1
Portuga
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- 6
Homework Statement
If A and B are square matrices of same order, prove of find a counter example that if AB = 0 then BA = 0.
Homework Equations
[tex]A^{-1} A = I_n, ABC = (AB)C [/tex]
The Attempt at a Solution
[tex] AB = 0 \Rightarrow A^{-1} A B = A^{-1} 0 \Rightarrow (A^{-1} A) B = A^{-1} 0 \Rightarrow I_n B = A^{-1} 0 \Rightarrow B = A^{-1} 0 \Rightarrow B = 0 \Rightarrow BA = 0A = 0. [/tex]
I am not pretty sure if this procedure really solve the problem, so I would like some advices...
Thanks in advance.