Here is some mathematica code to be used by my linear algebra students. The post will be periodically updated as the course progresses.

Entering matrices

Mathematica views matrices as lists of columns. Thus to enter the matrix

we type in

mat = {{1, 1, -1, -1}, {1, 2, 3, 4}, {1, 3, 5, 7}};

and hit [enter]. Here we have given the matrix the name mat and suppressed the output.

To view the matrix, type in the code

MatrixForm[mat]

and hit [enter].

Row reducing a matrix

To row reduce the matrix, type in the code

RowReduce[mat]

and hit [enter]. Notice that the output is just given in list format. To display the result as a matrix, you can use either

MatrixForm[RowReduce[mat]]

or

RowReduce[mat] // MatrixForm