Ex 4.2, 15 - Let A be a square matrix of order 3 x 3, then |kA|

Ex 4.2, 15 - Chapter 4 Class 12 Determinants - Part 2

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Question 15 Choose the correct answer. Let A be a square matrix of order 3 Ɨ 3, then |"kA" | is equal to A. "k" |"A" | B. "k" 2|"A" | C. "k" 3|"A" | D. 3"k" |"A" | Let A = [ā– 8(š‘Ž1&š‘1&š‘1@š‘Ž2&š‘2&š‘2@š‘Ž3&š‘3&š‘3)]_(3 Ɨ 3) We need to find |kA| kA = k [ā– 8(š‘Ž1&š‘1&š‘1@š‘Ž2&š‘2&š‘2@š‘Ž3&š‘3&š‘3)] = [ā– 8(š’Œš‘Ž1&š’Œš‘1&š’Œš‘1@š’Œš‘Ž2&š’Œš‘2&š’Œš‘2@š’Œš‘Ž3&š’Œš‘3&š’Œš‘3)] If a matrix is multiplied by a constant, then constant is multiplied to all elements of matrix |"kA" | = |ā– 8(š‘˜š‘Ž1&š‘˜š‘1&š‘˜š‘1@š‘˜š‘Ž2&š‘˜š‘2&š‘˜š‘2@š‘˜š‘Ž3&š‘˜š‘3&š‘˜š‘3)| Taking out k common from R1 R2 & R3 = k. k. k |ā– 8(a1&b1&c1@a2&b2&c2@a3&b3&c3)| = k3 |ā– 8(a1&b1&c1@a2&b2&c2@a3&b3&c3)| = k3 |A| Thus, Correct answer is C Property: If each element of row of determinant is multiplied by a constant k , then its value get multiplied by k

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