Identity matrix

In mathematics the identity matrix is the which does not change the size or values of a matrix under the operation of multiplication. The usually identity matrix is denoted $I$ or $I_{n}$, and the operation of multiplication is discribed as,

$AI=A$ or $IA=A$

The identity matrix is an $n\times n$ with a leading diagonal of ones and all other enteries are zero,

$I={\begin{bmatrix}1&0&\cdots &0\\0&1&\cdots &0\\\vdots &\vdots &\ddots &\vdots \\0&0&\cdots &1\end{bmatrix}}$.