Question 7 - CBSE Class 12 Sample Paper for 2025 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Last updated at Feb. 12, 2025 by Teachoo

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Question 7 If 𝐴=[■(0&1&𝑐@−1&𝑎&−𝑏@2&3&0)] is a skew-symmetric matrix then the value of 𝑎+𝑏+𝑐= (A) 1 (B) 2 (C) 3 (D) 4 In a skew symmetric matrix A’ = −A Putting values [■(0&−1&2@1&𝑎&3@c&−b&0)]=−[■(0&1&𝑐@−1&𝑎&−𝑏@2&3&0)] [■(0&−1&2@1&𝑎&3@c&−b&0)]=[■(−0&−1&−𝑐@−(−1)&−𝑎&−(−𝑏)@−2&−3&−0)] [■(0&−1&2@1&𝑎&3@c&−b&0)]=[■(0&−1&−𝑐@1&−𝑎&𝑏@−2&−3&0)] Since matrices are equal, its corresponding terms are equal. So, c = −2 b = 3 And, a = − a a + a = 0 2a = 0 a = 0 Thus, a + b + c = 0 + 3 − 2 = 1 So, the correct answer is (A)

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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 15 years. He provides courses for Maths, Science and Computer Science at Teachoo

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