EDMATH 300

A rectangular array of numbers, in which not only the value of the number is important but also its position in the array.

(a)  

The numbers in the array are called (a)   of the matrix.

The size of the matrix is described by the number of its (a)   .

The elements (or the entries) of a matrix are generally enclosed in brack-

ets, double-subscripting is used to index the elements. The First subscript

always denote the (a)   position.

The main diagonal in a square matrix contains the elements (a)  

A matrix is said to be (a)   if all its entries below the main

diagonal are 0.

A matrix is said to be (a)   if all its entries above the main

diagonal are 0.

If all the entries of a square matrix are zero, except those entries on the

main diagonal, then we say the matrix is a (a)   .