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CBSE Class 12 · MatricesVery Short Answer

If

A = 10 - 2 - 2 - 1 2 341

, find

(A^{'})^{- 1}

.

Answer: $(A^{'})^{- 1} = - 9 8 - 5 - 8 7 - 4 - 2 2 - 1$

Solution

Use

(A^{'})^{- 1} = (A^{- 1})^{'}

. First

A^{'} = 1 - 2 3 0 - 1 4 - 2 21

and

∣ A^{'} ∣ = ∣ A ∣ = 1 \neq = 0

.
Compute

adj (A^{'})

from the cofactors of

A^{'}

:

adj (A^{'}) = - 9 8 - 5 - 8 7 - 4 - 2 2 - 1 .

Since

∣ A^{'} ∣ = 1

,

(A^{'})^{- 1} = \frac{adj ( A ^{'} )}{∣ A ^{'} ∣} = - 9 8 - 5 - 8 7 - 4 - 2 2 - 1 .

CBSE Class 12 Board · Subjective

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