Let A be a 3 × 3 matrix such that adj A = 2 - 1 1 - 1 0 2 1 - 2 - 1 and B = adj a d j A . If | A | =…

Let A be a 3×3 matrix such that adjA=2-11-1021-2-1 and B=adjadjA. If |A|=λ and B-1⊤=μ, then the ordered pair λ, μ is equal to
  1. 3, 181
  2. 9, 19
  3. 3, 81
  4. 9, 181

Solution

adj A=A2=9

⇒A=±3=λ⇒λ=3

⇒B=adj A2=81

⇒B-1T=B-1=B-1=1B=181=μ

∴λ, μ=3, 181.

Asked in: JEE Main 2020 (03 Sep Shift 2)

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