Ex 4.5, 18 - If A is an invertible matrix of order 2, det(A-1) - Finding Inverse of a matrix

  1. Chapter 4 Class 12 Determinants
  2. Serial order wise

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

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