If A is a square matrix of order 3 , then true statement is (where I is unit matrix)

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3 and 4 .Determinants and Matrices

easy

If $ A $ is a square matrix of order $3$, then the true statement is (where $ I$ is unit matrix)

A

$det$ $( - A) = - \det A$

B

$det$ $A = 0$

C

$det$ $(A + I) = 1 + \det A$

D

$det$ $2A = 2\det A$

Solution

(a) Since $det$ $( – A) = {( – 1)^3}\det A = – \det A$.

Standard 12

Mathematics

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