CBSE Class 12 Math 2022 Term I Solved Paper - Question 13 | ...

CBSE Class 12 Math 2022 Term I Solved Paper

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Question : 13 of 50

Marks: +1, -0

If

C_{i j}

denotes the cofactor of element

P_{i j}

of the matrix

P={[\table 1 , -1 , 2 ; 0 , 2 , -3 ; 3 , 2 , 4]}

, then the value of

C_{31} ⋅ C_{23}

is

5
24
-24
-5

Solution:

Explanation:
Here,

C_{31}=(-1)^{3+1}{|\table -1 , 2 ; 2 , -3 |}=3-4=-1

C_{23}=(-1)^{2+3}{|\table 1 , -1 ; 3 , 2 |}=-(2+3)=-5

and

C_{23}=(-1)^{2+3}{|\table 1 , -1 ; 3 , 2 |}=-(2+3)=-5

Thus,

\;\; {\C}_{31} ⋅ {\C}_{23}=(-1)(-5)=5

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