Question 6 - CBSE Class 12 Sample Paper for 2021 Boards

Last updated at Oct. 27, 2020 by Teachoo

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

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

CBSE Class 12 Sample Paper for 2021 Boards

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.

Question 6 - CBSE Class 12 Sample Paper for 2021 Boards

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 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