If A is a square matrix of order 3 and |A| = 5, then |adjA|=

(a) 5  

(b) 25  

(c) 125  

(d) 1/5

 

This question is Similar to Question-1 CBSE - Class-12 - Sample-Paper-for-2020-Boards

Slide27.JPG

Slide28.JPG


Transcript

Question 13 If A is a square matrix of order 3 and |A| = 5, then |𝑎𝑑𝑗𝐴|= (a) 5 (b) 25 (c) 125 (d) 1/5 We know that |𝒂𝒅𝒋 𝑨| = |𝑨|^(𝒏−𝟏) where n is the order of determinant Given Order = n = 3 So, |𝒂𝒅𝒋 𝑨| = |𝑨|^(𝟑−𝟏) |𝑎𝑑𝑗 𝐴| = |A|^2 |𝑎𝑑𝑗 𝐴| = 52 |𝒂𝒅𝒋 𝑨| = 25 So, 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 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.