(i) Find the combined sales in September and October for each farmer in each variety.
(ii) Find the decrease in sales from September to October.
(iii) If both farmers receive 2% profit on gross sales, compute the profit for each farmer and for cach variety sold in October.
X, Z are matrices of order 2 x 2 X p respectively.
If n = p, then the order of the matrix 7X – 5Z is :
p x 2
2 x n
n x 3
n x 3
Show that AB ≠ BA.
A is of type 2 x 3 and B is of type 3 x 2.
Since number of columns of A = number of rows of B =3
∴ AB is defined.
Again number of columns of B = number of rows of A = 2
∴ BA is defined.
Note 1. From above example, it is clear that though AB and BA are defined, yet AB ;≠ BA. Here A and B are of different types.
Note 2. Even if A and B are of same order, there are chances that AB≠ BA.
∴ we can say that matrix multiplication is not commutative.
Note 3. Even if AB ≠ BA in many cases, there are cases when AB = BA.