1.

If `A=[(1,2,-1),(-1,1,2),(2,-1,1)]`, then det (adj(adj A) isA. `14^4`B. `14^3`C. `14^2`D. 14

Answer» Correct Answer - A
We know that for a square matrix of order n
adj (adjA)`=abs(A)^(n-2)A," if " absA ne 0`.
`rArr "det (adj(adj A))" abs(abs(A)^(n-2)A)`
`rArr "det (adj(adj A)) "(abs(A)^(n-2))^nabsA`
`rArr " det(adj)(adj A))" =abs(A)^(n^2-2n+1)`
Here, n=3 and and `absA=14`.
`:. " det(adj(adj A))"=14^4`


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