Answer problems 13 using the following matrices A 1 2 1 2 0

Answer problems 1–3 using the following matrices: A = [1 -2 1 -2 0 2 ] B = [2 0 2 1 1 1 0 2 0 ]

1) Identify the following values: a13 = , a21 = , b12 = , b21 =

2) Compute A + A.

3) Of A•B and B•A, only one product is defined.

Explain which product is undefined and why.

Evaluate the product that is defined.

Solution

1. a13 = 1 (in first row 3rd element), a21 = -2 in 2nd row 1st element b12 = 0 , b21 = 1

2. a+a = adding individual ement [1+1 -2+-2 1+1 2+2 0+0 2+2 ] =[2 -4 2 4 0 4]

3. Ab is defined since in matrix multiplication of two matrices with dimensio m*n and n*k , number of columns n in one matrices is equal to number of rowsanother matrix

here A\'s dimension is 2*2 and B\'s dimension is 2*5 hence by above logic they are compatible

on the other hand , BA is not possible