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If a = ∣ ∣ ∣ ∣ a 11 a 12 a 13 a 21 a 22 a 23 a 31 a 32 a 33 ∣ ∣ ∣ ∣ and Cij is Cofactor of Aij in A, Then Value of |A| is Given (A) A11 C31 + A12 C32 + A13 C33 (B) A11 C11 + A12 C21 + A1

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Question

If \[A = \begin{vmatrix}a_{11} & a_{12} & a_{13} \\ a_{21} & a_{22} & a_{23} \\ a_{31} & a_{32} & a_{33}\end{vmatrix}\]  and Cij is cofactor of aij in A, then value of |A| is given 



Options

  • a11 C31 + a12 C32 + a13 C33

  • a11 C11 + a12 C21 + a13 C31

  • a21 C11 + a22 C12 + a23 C13

  •  a11 C11 + a21 C21 + a13 C31

MCQ
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Solution

(d) a11 C11 + a21 C21 + a13 C31
Properties of determinants state that if is a square matrix of the order n, then Det (A) is the sum of products of elements of a row (or a column) with the corresponding cofactor of that element.

\[\left| A \right| = a_{11} C_{11} + a_{21} C_{21} + a_{31'} C_{31} \left[\text{ Calculating along }C_1 \right]\]
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Chapter 5: Determinants - Exercise 6.7 [Page 93]

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R.D. Sharma Mathematics Volume 1 and 2 [English] Class 12
Chapter 5 Determinants
Exercise 6.7 | Q 3 | Page 93

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