Thread: Problem 38
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Old October 28th, 2007, 02:40 PM
putnam120 putnam120 is offline
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I am not sure but is this what you are saying?

Let A be any n\times n invertible matrix. Now if B is an n\times n matrix such that AB=BA for any choice of A then B is a scalar multiple of the identity matrix. That is B=kI.