Check sibling questions

For A = [8(3 1 -1 2)], then 14 A −1 is given by

(a) 14 [8(2 -1 1 3)]    (b) [8(4 -2 2 6)]

(c) [8(2 -1 1 -3)]        (d) 2 [8(-3 -1 1 -2)]  

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Question 38 For A = [■8(3&[email protected]−1&2)], then 14 A−1 is given by (a) 14 [■8(2&−[email protected]&3)] (b) [■8(4&−[email protected]&6)] (c) [■8(2&−[email protected]&−3)] (d) 2 [■8(−3&−[email protected]&−2)] We know that A-1 = 1/(|A|) adj A Now, |𝑨| = |■8(3&[email protected]−1&2)| = 3 × 2 – (−1) × 1 = 6 + 1 = 7 So, the correct answer is (B) A =[■8(3&[email protected]−1&2)] Now, adj A = [■8(3&[email protected]−1&2)] = [■8(𝟐&−𝟏@𝟏&𝟑)] Thus, A-1 = 1/(|A|) adj A = 1/7 [■8(2&−[email protected]&3)] So, 14A-1 = 14 × 1/7 [■8(2&−[email protected]&3)] = 2 [■8(2&−[email protected]&3)] = [■8(2 × 2&2 × −[email protected] × 1&2 × 3)] = [■8(𝟒&−𝟐@𝟐&𝟔)] So, the correct answer is (B)

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.