Create the matrix:

A = np.mat("3 4;5 6")
print("A\n", A)

The matrix we created appears as follows:

A
[[ 3.  4.]
 [ 5.  6.]]

Compute the determinant with the det() function:

print("Determinant", np.linalg.det(A))

The determinant appears as follows:

Determinant -2.0