Identity Matrices

## Description

We can use the `identity_matrix()` command to create an identity matrix of any dimension, say

\begin{align} I = \begin{pmatrix} 1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1 \end{pmatrix}, \end{align}

## Sage Cell

#### Code

```
id3 = identity_matrix(QQ, 3)
id3
```

## Options

None.

## Tags

CC:

Primary Tags: Linear algebra: Matrices.

Secondary Tags: Matrices: Matrix basics, Matrix inverses.

## Related Cells

- Matrices in Sage. Matrices in Sage.
- Elementary Row Operations on Matrices Using Sage to perform elementary row operations.
- The determinant of a matrix. Taking the determinant of a matrix.
- The product of two matrices. Calculating the product of two matrices.
- The rank of a matrix. Calculating the rank of a matrix.
- The RREF of a matrix. Computing the RREF of a matrix.
- Finding the Pivot Columns of a Matrix. Finding the pivot columns of a matrix.
- Finding the Free Columns of a Matrix. Finding the free columns of a matrix.
- Testing a Matrix for Singularity. Testing a given matrix to see if it is singular (noninvertible).

## Attribute

Permalink:

Author: R. Beezer

Date: 01 Mar 2020 21:11

Submitted by: Zane Corbiere