Adjoint of the matrix A = [aij]n×n is defined as the transpose of the matrix [Aij]n×n where Aij is the co-factor of the element aij.
Let’s find the cofactors for all the positions first-
Here, A11 = -1, A12 = 0, A13 = 0, A21 = 0, A22 = -cosα, A23 = -sinα, A31 = 0, A32 = -sinα, A33 = cosα.
∴ Adj A =
And |A| = 1.
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