CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)

Question 17 - CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1) - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Last updated at Sept. 4, 2021 by Teachoo

Given that A = [๐๐๐] is a square matrix of order 3 × 3 and |A| = −7, then the value of ∑_(i=1)
^{
3
}
a
_{
i2
}
A
_{
i2
}
" , where ๐ด
_{
๐๐
}
denotes the cofactor of element ๐๐๐ is:

Question 17 Given that A = [๐๐๐] is a square matrix of order 3 ร 3 and |A| = โ7, then the value of โ_(๐=1)^3โ"๐๐2๐ด๐2 " , where ๐ด๐๐ denotes the cofactor of element ๐๐๐ is: (a) 7 (b) โ7 (c) 0 (d) 49
Now,
= ๐_๐๐ ๐จ_๐๐+๐_๐๐ ๐จ_๐๐+๐_๐๐ ๐จ_๐๐
= Sum of product of elements of Row R2 with its corresponding cofactors
= Determinant of A
= |A|
= 7
So, the correct answer is (B)

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CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)

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.