Identity matrix

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An identity matrix is a square matrix of size \( n \times n \), where the diagonal elements are all 1s (ones), and all the other elements are all 0s (zeroes).

• \(\displaystyle I_{n}=\begin{bmatrix} 1 & 0 & 0 \cr 0 & 1 & 0 \cr 0 & 0 & 1 \cr \end{bmatrix}\)