Basic Matrix Operations
Some basic matrix operations.
Transposing a matrix interchanges the rows and columns in the matrix. If you transpose an m×n matrix, you get an n×m matrix as the result.
Transposing a 2×3 matrix gives a 3×2 result.
Det [m] gives the determinant of a square matrix
m.
Minors [m] is the matrix whose
^(th) element gives the determinant of the submatrix obtained by deleting the
^(th) row and the
^(th) column of
m. The
^(th) cofactor of
m is times the
^(th) element of the matrix of minors.
Minors gives the determinants of the
k×
k submatrices obtained by picking each possible set of
k rows and
k columns from
m. Note that you can apply
Minors to rectangular, as well as square, matrices.
Here is the determinant of a simple 2×2 matrix.
This generates a 3×3 matrix, whose ^(th) entry is .
Here is the determinant of .
The
trace or
spur of a matrix
Tr [m] is the sum of the terms on the leading diagonal.
This finds the trace of a simple 2×2 matrix.
The rank of a matrix is the number of linearly independent rows or columns.
This finds the rank of a matrix.
Powers and exponentials of matrices.
Here is a 2×2 matrix.
This gives the third matrix power of .
It is equivalent to multiplying three copies of the matrix.
Here is the millionth matrix power.
The matrix exponential of a matrix m is , where indicates a matrix power.
This gives the matrix exponential of .
Here is an approximation to the exponential of , based on a power series approximation.