Question

When determinant of a matrix not defined?

Answer 1

The determinant of a matrix is defined only for square matrices. For matrices of type mxn, determinant is not defined.

Answer 2

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When we put this matrix in reduced echelon form, we found that one of the steps was to divide each member of the matrix by the determinant, so if the determinant is 0, we cannot do that division, and therefore we cannot put the matrix in the form of the identity matrix, and therefore the matrix is not invertible.