Calculating the determinant of a square matrix on Matlab

The det() function in MATLAB is used to calculate the determinant of a square matrix.

det(M)

Here, M is the matrix input, which is the function’s only parameter.

The det() function returns the determinant of M if it exists.

If the determinant does not exist, the function returns zero.

Note: Determinants can only be calculated for square matrices, which have an equal number of rows and columns. Learn more about determinants.

For example, let’s define a square matrix stored in M.

This matrix is of order 2.

M = [ 1 2 ; 3 4 ]

We can calculate the determinant by running det(M):

>> det(M)

The determinant of this matrix is -2.

ans = -2

Now, let’s define another matrix in M, this time a 3x3 matrix:

M = [ 1 2 3 ; 4 5 6 ; 7 8 9 ]

Using the det(M) function again, we calculate the determinant of this matrix.

det(M)

The result is a very small number:

ans = 6.6613e-16

This indicates that the determinant is effectively zero.

To make results clearer, I use the round() function to reduce small decimal values:

round(det(M), 5)

>> round(det(M), 5)

Now, the result is displayed as:

ans = 0

This confirms that matrix M has no non-zero determinant.