Chapter 3 Class 12 Matrices
Concept wise

This video is only available for Teachoo black users

This video is only available for Teachoo black users

This video is only available for Teachoo black users

This video is only available for Teachoo black users

This video is only available for Teachoo black users

Introducing your new favourite teacher - Teachoo Black, at only ₹83 per month

### Transcript

Ex 3.2, 1 Let A = [■8(2&4@3&2)], B = [■8(1&3@−2&5)], C = [■8(−2&5@3&4)] Find each of the following (i) A + B A + B = [■8(2&4@3&2)] + [■8( 1&3@−2&5)] = [■8(2+1&4+3@3−2&2+5)] = [■8(𝟑&𝟕@𝟏&𝟕)] Ex 3.2,1 Let A = [■8(2&4@3&2)], B = [■8(1&3@−2&5)], C = [■8(−2&5@3&4)] Find each of the following (ii) A – B A – B = [■8(2&4@3&2)]− [■8( 1&3@−2&5)] = [■8(2−1&4−3@3−(−2)&2−5)] = [■8(1&1@3+2&−3)] = [■8(𝟏&𝟏@𝟓&−𝟑)] Ex 3.2, 1 Let A = [■8(2&4@3&2)], B = [■8(1&3@−2&5)], C = [■8(−2&5@3&4)] Find each of the following 3A – C Finding 3A 3A = 3[■8(2&4@3&2)] = [■8(3 × 2&3 × 4@3 × 3 &3 × 2)] = [■8(𝟔&𝟏𝟐@𝟗&𝟔)] Hence 3A – C = [■8(6&12@9&6)] ⤶7− [■8(−2&5@3&4)] = [■8(6−(−2)&12−5@9−3&6−4)] = [■8(6+2&7@6&2)] = [■8(𝟖&𝟕@𝟔&𝟐)] Ex 3.2, 1 Let A = [■8(2&4@3&2)] B = [■8(1&3@−2&5)] , C = [■8(−2&5@3&4)]. Find each of the following (iv)AB AB = [■8(2&4@3&2)] [■8(1&3@−2&5)] = [■8(2 × 1+4 × −2 &2 × 3+4 × 5@3 × 1+2 × −2&3 × 3+2 × 5)] = [■8(2−8&6+20@3−4&9+10)] = [■8(−𝟔&𝟐𝟔@−𝟏&𝟏𝟗)] Ex 3.2, 1 Let A = [■8(2&4@3&2)] B = [■8(1&3@−2&5)] , C = [■8(−2&5@3&4)]. Find each of the following (v) BA BA = [■8(1&3@−2&5)] [■8(2&4@3&2)] = [■8(1 × 2+3 × 3 &1 × 4+3 × 2@−2 × 2+5 × 3&−2 × 4+5 × 2)] = [■8(2+9&4+6@−4+15&−8+10)] = [■8(𝟏𝟏&𝟏𝟎@𝟏𝟏&𝟐)]