Given that A is a square matrix of order 3 and |A| = −4, then adj A| is equal to:

(a) −4     (b) 4
(c) −16   (d) 16

This question is inspired from Question 5 (Choice 2) - CBSE Class 12 Sample Paper for 2021 Boards

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

Transcript

Question 6 Given that A is a square matrix of order 3 and |A| = โˆ’4, then adj A| is equal to: (a) โˆ’4 (b) 4 (c) โˆ’16 (d) 16 We know that |๐’‚๐’…๐’‹ ๐‘จ| = |๐‘จ|^(๐’โˆ’๐Ÿ) where n is the order of determinant Given Order = n = 3 So, |๐‘Ž๐‘‘๐‘— ๐ด| = |A|^(3โˆ’1) |๐‘Ž๐‘‘๐‘— ๐ด| = |A|^2 |๐‘Ž๐‘‘๐‘— ๐ด| = (โˆ’4)2 |๐’‚๐’…๐’‹ ๐‘จ| = 16 So, the correct answer is (d)

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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.