Example 25 - Find P-1, given P = [10 -2 -5 1] - Matrices

Example 25 - Chapter 3 Class 12 Matrices - Part 2

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Question 3 Find P -1, if it exists, given P = [■8(10&−2@−5&1)] Given P = [■8(10&−2@−5&1)] We know that P = I P [■8(10&−2@−5&1)] = [■8(1&0@0&1)] P R1 →1/10 R1 [■8(𝟏𝟎/𝟏𝟎&(−2)/10@−5&1)]" = " [■8(1/10&0/10@0&1)]" P" [■8(𝟏&(−1)/5@−5&1)] = [■8(1/10&0@0&1)] P R2 →"R2" + 5R1 [■8(1&(−1)/5@−𝟓+𝟓(𝟏)&1+5((−1)/5) )]" = " [■8(1/10&0@0+5(1/10)&1+5(0))]" P" [■8(1&(−1)/5@−𝟓+𝟓&1−1)]" = " [■8(1/10&0@0+(1/2)&1+0)]" P" [■8(1&(−1)/5@𝟎&0)] = [■8(1/10&0@1/2&1)] P Since we have all zeros in the second row of the left hand side matrix of the above equation. Therefore, P–1 does not exist.

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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