Check sibling questions

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

CBSE Class 12 Sample Paper for 2021 Boards →
Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Question 38 - 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 March 22, 2023 by

For A = [8(3 1 -1 2)], then 14 A −1 is given by

(a) 14 [8(2 -1 1 3)]    (b) [8(4 -2 2 6)]

(c) [8(2 -1 1 -3)]        (d) 2 [8(-3 -1 1 -2)]  

Slide98.JPG

Slide99.JPG
Slide100.JPG

This video is only available for Teachoo black users

Subscribe Now

Get live Maths 1-on-1 Classs - Class 6 to 12

Book 30 minute class for ₹ 499 ₹ 299

Transcript

Question 38 For A = [■8(3&[email protected]−1&2)], then 14 A−1 is given by (a) 14 [■8(2&−[email protected]&3)] (b) [■8(4&−[email protected]&6)] (c) [■8(2&−[email protected]&−3)] (d) 2 [■8(−3&−[email protected]&−2)] We know that A-1 = 1/(|A|) adj A Now, |𝑨| = |■8(3&[email protected]−1&2)| = 3 × 2 – (−1) × 1 = 6 + 1 = 7 So, the correct answer is (B) A =[■8(3&[email protected]−1&2)] Now, adj A = [■8(3&[email protected]−1&2)] = [■8(𝟐&−𝟏@𝟏&𝟑)] Thus, A-1 = 1/(|A|) adj A = 1/7 [■8(2&−[email protected]&3)] So, 14A-1 = 14 × 1/7 [■8(2&−[email protected]&3)] = 2 [■8(2&−[email protected]&3)] = [■8(2 × 2&2 × −[email protected] × 1&2 × 3)] = [■8(𝟒&−𝟐@𝟐&𝟔)] So, the correct answer is (B)

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.