MHB Proving the Inverse of the Adjoint Matrix Property for nxn Matrices

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Hello

I need some help proving the next thing, I can't seem to be able to work it out..

Let A be an nxn matrix.

Prove that:

(adj A)^{-1} = adj(A^{-1})

Thanks...
 
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$A = IA = A^*(A^*)^{-1}A$

so:

$A^* = (A^*(A^*)^{-1}A)^* = A^*((A^*)^{-1})^*A$

therefore:

$A^*A^{-1} = A^*((A^*)^{-1})^*$

and multiplying on the left by $(A^*)^{-1}$ we get:

$A^{-1} = ((A^*)^{-1})^*$

so

$(A^{-1})^* = ((A^*)^{-1})^{**} = (A^*)^{-1}$
 
thanks, took me some time to understand your proof, but now I see it, nice one !
(Yes)
 
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