2. Getting acquainted with matrices.. Let A be an n x n matrix. Notice that the diag- onal entries of A are Ali,i,-0,...n-1 while Ali,j is above the diagonal if i j. Furthermore, consider a particular entry like A3,7.If we traverse the matrix to the left until we hit the diagonal, we encounter A3, 6, A3,5], A3,4], A3,3; on the other hand, if we traverse the matrix downwards until we hit the diagonal, we encounter A4,7, 5,7, A(, 7, Air, 71. That is, we en- counter the same number of entries when we start from A|3,7 and go to the left until we hit the diagonal or go downwards until we hit the diagonal. This observation turns out to be true for all .jl, i j. Furthermore, consider a particular entry like A3,7.If we traverse the matrix to the left until we hit the diagonal, we encounter A3, 6, A3,5], A3,4], A3,3; on the other hand, if we traverse the matrix downwards until we hit the diagonal, we encounter A4,7, 5,7, A(, 7, Air, 71. That is, we en- counter the same number of entries when we start from A|3,7 and go to the left until we hit the diagonal or go downwards until we hit the diagonal. This observation turns out to be true for all .jl, i