Adjoint of a matrix
Matrices and determinants (introductory) · Mathematics
Study notes
Q: Find adj and inverse of A = [[3,2],[1,4]]. Cofactors: C₁₁=4, C₁₂=-1, C₂₁=-2, C₂₂=3. Cofactor matrix [[4,-1],[-2,3]]. adj(A) = transpose = [[4,-2],[-1,3]]. det = 10. A⁻¹ = (1/10)[[4,-2],[-1,3]]. Check: A·A⁻¹ = I ✓.