Compute AB and BA, which ever exists when A = [1 2 3 4] and

Question

Philoid · Accepted Answer

Given : A = [1 2 3 4] and

Matrix A is of order 1 4 and Matrix B is of order 4 1

To find : matrices AB and BA

Formula used :

Where c_ij = a_i1b_1j + a_i2b_2j + a_i3b_3j + ……………… + a_inb_nj

If A is a matrix of order a b and B is a matrix of order c d ,then matrix AB exists and is of order a d ,if and only if b = c

If A is a matrix of order a b and B is a matrix of order c d ,then matrix BA exists and is of order c b ,if and only if d = a

For matrix AB, a = 1,b = 4,c = 4,d = 1 ,matrix AB exists and is of order 1 1,as

b = c = 4

Matrix AB =

Matrix AB = =

Matrix AB =

For matrix BA, a = 1,b = 4,c = 4,d = 1 ,matrix BA exists and is of order 4 4,as

d = a = 1

Matrix BA =