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If A=[(1+2i,i),(-I,1-2i)], where i=sqrt(...

If `A=[(1+2i,i),(-I,1-2i)]`, where `i=sqrt(-1)`, then `A(adjA)=`. . .

A

`-2l`

B

2l

C

5 l

D

4l

Text Solution

Verified by Experts

The correct Answer is:
D
We have, `A = [{:(1 +2i, i),(-I,1-2i):}]`
`:. |A| = |{:(1 + 2i, i),(-I,1-2i):}| = (1 + 2i) (1 - 2i) + i^(2)`
`= 1 - (2i)^(2) + (-1) = 1 + 4 - 1 = 4`
`:. A` (adj A) = |A| I = 4I
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