# Ex 4.5, 18 - Chapter 4 Class 12 Determinants

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Ex 4.5, 18 If A is an invertible matrix of order 2, then det(A 1) is equal to A. det (A) B. 1 det (A) C. 1 D. 0 We know that AA-1 = I Taking determinant both sides AA 1 = |I| |A| |A-1| = |I| |A| |A-1| = 1 |A-1| = 1 |A| Since |A| 0 Hence, |A-1| = 1 |A| is valid Thus, the correct answer is B

Chapter 4 Class 12 Determinants

Serial order wise

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.