Let A be a square matrix of order 3 x 3. Then |adj A| is - Teachoo - Ex 4.4

part 2 - Ex 4.4, 17 (MCQ) - Ex 4.4 - Serial order wise - Chapter 4 Class 12 Determinants
part 3 - Ex 4.4, 17 (MCQ) - Ex 4.4 - Serial order wise - Chapter 4 Class 12 Determinants

Take a fresh quiz. Then take another.
Every attempt is a new AI-adaptive Teachoo quiz with 3 questions, selected from your answers, mistakes, and progress.
Remove Ads

Transcript

Ex 4.4, 17 (Method 1) Let A be a nonsingular square matrix of order 3 Ɨ 3. Then |adj A| is equal to A. |A| B. |A|2 C. |A|3 D. 3 |A| We know that |š‘Žš‘‘š‘— š“| = |š“|^(š‘› āˆ’ 1) where n is the order of Matrix A Here, n = 3 |š‘Žš‘‘š‘— š“| = |š“|^(3 āˆ’ 1) = |š“|^2 Hence, B is the correct answer Ex 4.4, 17 (Method 2) Let A be a nonsingular square matrix of order 3 Ɨ 3. Then |adj A| is equal to A. |A| B. |A|2 C. |A|3 D. 3 |A| We know that A (adj A) = |A|I Taking determinants both sides |A (ad jA)| = ||A|I| Solving |A (adj (A))| |A (adj (A))| = |A| |adj (A)| Solving ||A|I| ||A|I| = |A|3|I| = |A|3 Now, |A (ad jA)| = ||A|I| Putting values |A| |adj (A)| = |A|3 |adj (A)| = |A|3/|A| |adj (A)| = |A|2 Thus, B is the correct answer

Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh is an IIT Kanpur graduate and has been teaching for 16+ years. At Teachoo, he breaks down Maths, Science and Computer Science into simple steps so students understand concepts deeply and score with confidence.

Many students prefer Teachoo Black for a smooth, ad-free learning experience.