Study guide and 1 practice problem on:

## Inverse of a 3x3 matrix

To find the inverse of a $3 \times 3$ matrix,
1. Compute the minors of each element
2. Negate every other element, according to a checkerboard pattern
3. Take the transpose
4. Divide by the determinant of the original matrix
Pictorially, this can be represented as:
The minor of the $(i,j)$th entry of a matrix $\bfA$ is the determinant of the submatrix obtained by removing the $i$th row and the $j$th column of $\bfA$.