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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 Oct. 27, 2020 by

Let A = [๐‘Ž๐‘–๐‘—] be a square matrix of order 3×3 and |A|= -7. Find the value of
๐‘Ž 11 ๐ด 21 + ๐‘Ž 12 ๐ด 22 + ๐‘Ž 13 ๐ด 23  where ๐ด ๐‘–๐‘— is the cofactor of element ๐‘Ž ๐‘–j

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

 

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

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Transcript

Question 6 Let A = [๐‘Ž๐‘–๐‘—] be a square matrix of order 3 ร— 3 and |A|= โˆ’7. Find the value of ๐‘Ž11 ๐ด21 + ๐‘Ž12 ๐ด22 + ๐‘Ž13 ๐ด23 where ๐ด๐‘–๐‘— is the cofactor of element ๐‘Ž๐‘–j We know that ๏ปฟIf elements of a row (or column) are multiplied with cofactors of any other row (or column), then their sum is zero Thus, ๐‘Ž11 ๐ด21 + ๐‘Ž12 ๐ด22 + ๐‘Ž13 ๐ด23 = 0

Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 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 10 years. He provides courses for Maths and Science at Teachoo.