Ex 3.4, 1 - Find inverse of [1 -1 2 3] - Chapter 3 Class 12 - Ex 3.4

part 2 - Question 1 - Ex 3.4 - Serial order wise - Chapter 3 Class 12 Matrices
part 3 - Question 1 - Ex 3.4 - Serial order wise - Chapter 3 Class 12 Matrices

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Ex 3.4, 1 Find the inverse of each of the matrices, if it exists. [■8(1&−1@2&3)] Let A = [■8(1&−1@2&3)] We know that A = IA [■8(1&−1@2&3)] = [■8(1&0@0&1)] A R2 → R2 – 2R1 [■8(1&−1@𝟐−𝟐(𝟏)&3−2(−1))] = [■8(1&0@0−2(1)&1−2(0))] A [■8(1&−1@𝟎&5)] = [■8(1&0@−2&1)] A R2 →1/5 R2 [■8(1&−1@0/5&𝟓/𝟓)] = [■8(1&0@(−2)/5&1/5)] A [■8(1&−1@0&𝟏)] = [■8(1&0@(−2)/5 " " &1/5 " " )] A R1 →R1 + R2 [■8(1+0&−𝟏+𝟏@0&1)] = [■8(1−2/5&0+1/5@(−2)/5 " " &1/5 " " )] A [■8(1&𝟎@0&1)] = [■8(3/5&1/5@(−2)/5 " " &1/5 " " )] A I = [■8(3/5&1/5@(−2)/5 " " &1/5 " " )] A This is similar to I = A-1A Thus, A-1 = [■8(𝟑/𝟓&𝟏/𝟓@(−𝟐)/𝟓 " " &𝟏/𝟓 " " )]

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo