- #1
tatianaiistb
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Homework Statement
If the entries of A and A^-1 are all integers, how do you know that both determinants are 1 or -1?
Homework Equations
The Attempt at a Solution
I know that
1 = det I = detAA-1=detA * detA-1= detA*(1/detA) = 1
Not sure how we get to - or the role integers play in it.
Thanks for your help!