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

Given that A = [π‘Žπ‘–π‘—] is a square matrix of order 3 Γ— 3 and |A| = βˆ’7, then the value of βˆ‘_(i=1) 3 a i2 A i2 " Β , where 𝐴 𝑖𝑗 denotes the cofactor of element π‘Žπ‘–π‘— Β is:

(a) 7Β  (b) βˆ’7Β  (c) 0Β  (d) 49

CBSE Sample Paper Class 12 - 2022 Boards.jpg

This video is only available for Teachoo black users

Introducing your new favourite teacher - Teachoo Black, at only β‚Ή83 per month


Transcript

Question 17 Given that A = [π‘Žπ‘–π‘—] is a square matrix of order 3 Γ— 3 and |A| = βˆ’7, then the value of βˆ‘_(𝑖=1)^3β–’"π‘Žπ‘–2𝐴𝑖2 " , where 𝐴𝑖𝑗 denotes the cofactor of element π‘Žπ‘–π‘— is: (a) 7 (b) βˆ’7 (c) 0 (d) 49 Now, = 𝒂_𝟏𝟐 𝑨_𝟏𝟐+𝒂_𝟐𝟐 𝑨_𝟐𝟐+𝒂_𝟐𝟐 𝑨_𝟏𝟐 = Sum of product of elements of Row R2 with its corresponding cofactors = Determinant of A = |A| = 7 So, the correct answer is (B)

Davneet Singh's photo - Teacher, Engineer, Marketer

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.