More Algebra

What happens when you multiply a matrix by the identity matrix?

When you multiply any n-by-n matrix by the identity matrix, you get that same matrix back again. Therefore, let the letter I represent the n-by-n identity matrix, and A represent any other n-by-n matrix; then we have A × I = A and I × A = A. This is much like the situation in the real numbers: x × 1 = x and 1 × x = x.


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