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UPSC NDA I and II 2020 Math Solved Paper
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© examsnet.com
Question : 5
Total: 120
Consider the following in respect of a non-singular matrix of order 3 :
1.
A
(
adj
A
)
=
(
adj
A
)
A
2.
|
adj
A
|
=
|
A
|
Which of the above statements is/are correct?
[NDA-I 2020]
1 only
2 only
Both 1 and 2
Neither 1 nor 2
Validate
Solution:
👈: Video Solution
(1) We know that,
A.(adj A) = (adj A)A = |A|.I
Hence, statement (1) is correct.
(2)
|
adj
(
A
)
=
|
A
−
1
.
|
A
|
|
Hence, statement (2) is not correct.
© examsnet.com
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