Texas Instruments TI-83 PLUS - Manual (Page 283)

TI-83 Plus Matrices 280
cumSum( matrix )
Row Operations
MATRX MATH
menu items A through F are row operations. You can use a
row operation in an expression. Row operations do not change matrix in
memory. You can enter all row numbers and values as expressions. You
can select the matrix from the
MATRX NAMES
menu.
ref(, rref(
ref( (row-echelon form) returns the row-echelon form of a real matrix . The
number of columns must be greater than or equal to the number of rows.
ref( matrix )
rref( (reduced row-echelon form) returns the reduced row-echelon form of
a real matrix . The number of columns must be greater than or equal to the
number of rows.