The identity matrix, denoted as $I$, is a square matrix in which all the elements of the principal diagonal are ones, and all other elements are zeros. For a $5 \times 5$ matrix, it looks like this:
\[
I = \begin{array}{ccccc}
1 & 0 & 0 & 0 & 0 \\
0 & 1 & 0 & 0 &
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