Ex 3.3

Chapter 3 Class 12 Matrices
Serial order wise

This video is only available for Teachoo black users

Get live Maths 1-on-1 Classs - Class 6 to 12

### Transcript

Ex 3.3, 5 For the matrices A and B, verify that (AB) = B A where (i) A = [ 8([email protected] [email protected])] , B = [-1 2 1] Taking L.H.S (AB) Finding AB first AB =[ 8([email protected] [email protected])]_(3 1) "[ 1 2 1] " _(1 3) = [ 8(1 ( 1) &1 2&1 [email protected] 4 ( 1)& 4 2& 4 [email protected] ( 1)&3 2&3 1)]_(3 3) = [ 8( 1&2&[email protected]& 8& [email protected] 3&6&3)] AB = [ 8( 1&2&[email protected]& 8& [email protected] 3&6&3)] Now, (AB) = [ 8( 1&4& [email protected]& 8&[email protected]& 4&3)] Taking R.H.S B A Finding B , A Given B = [ 1 2 1] B = "[" "1 2 1]" ^ = [ 8( [email protected]@1)] Given A = [ 8([email protected] [email protected])] A = [1 4 1] Now, B A = [ 8( [email protected]@1)]_(3 1) "[1 4 3]" _(1 3) = [ 8( 1 1& 1 ( 4)& 1 [email protected] 1&2 ( 4)&2 [email protected] 1&1 ( 4)&1 3)]_(3 3) = [ 8( 1&4& [email protected]& 8&[email protected]& 4&3)] = L.H.S Hence L.H.S = R.H.S Hence proved