Invertible matrix
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An invertible matrix A is one that has a corresponding matrix B such that:
- AB = BA = I (I: identity matrix)
A matrix is invertible if and only if it has a nonzero determinant. Only square matrices (n x n) are invertible.
It can be shown that, for any invertible matrix A, there is only one matrix B such that AB = I; this unique matrix is called the inverse matrix of A, and represented as A-1.