Top 10 Matlab Commands for Linear Algebra Students

1. basic input: "A = [ 1 2 3; -1 2 3; 2 4 5 ]" inputs a 3x3 matrix by rows; variants
"b = [ -1 2 1]' " or "b = [ -1; 2; 1]" to input a column vector b, and
"C = [ A b ]" to produce a matrix C containing A augmented with b.
Note: "format compact" reduces output spaces; also try "format long", "format rat", "help format".
2. rref: "rref(A)" reduces A to reduced echelon form; see also "rrefmovie(A)".
3. basic arithmetic: "A*B", "A+B", "A\b" to multiply and add matrices, solve Ax = b.
4. help: "help command" gives information about "command", e.g. "help rref".
Note: "more on" gives output (e.g. from help) one screen at a time.
5. lookfor: "lookfor keyword" tries to find commands relevant to "keyword"; e.g. "lookfor null".
6. diary: "diary myfile" records subsequent output in the file "myfile" for printing later;
"diary off" stops the recording; "!mail name@email.address < myfile" emails "myfile" to "name@email.address" from a computer with a Unix OS.
7. rand: "rand(6,4)" produces a random 6x4 matrix.
8. det: "det(A)" computes the determinant of a square matrix A.
9. inv: "inv(A)" tries to compute the inverse of a square matrix A.
10. eig: "eig(A)" computes eigenvalues(vectors) for square A; try "help eig" for more info.

Note: the uparrow key gives previous commands that may be edited to save typing; this only works if your keyboard characterstics are properly recognized.