CBSE Class 12 Sample Paper for 2021 Boards

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Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Question 6 - CBSE Class 12 Sample Paper for 2021 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Last updated at April 16, 2024 by

Let A = [𝑎𝑖𝑗] be a square matrix of order 3×3 and |A|= -7. Find the value of
𝑎 11 𝐴 21 + 𝑎 12 𝐴 22 + 𝑎 13 𝐴 23  where 𝐴 𝑖𝑗 is the cofactor of element 𝑎 𝑖j

Let A = [aij] be a square matrix of order 3×3 and |A|= -7. Find value

 

Transcript

Question 6 Let A = [𝑎𝑖𝑗] be a square matrix of order 3 × 3 and |A|= −7. Find the value of 𝑎11 𝐴21 + 𝑎12 𝐴22 + 𝑎13 𝐴23 where 𝐴𝑖𝑗 is the cofactor of element 𝑎𝑖j We know that If elements of a row (or column) are multiplied with cofactors of any other row (or column), then their sum is zero Thus, 𝑎11 𝐴21 + 𝑎12 𝐴22 + 𝑎13 𝐴23 = 0

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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, Social Science, Physics, Chemistry, Computer Science at Teachoo.