Question Bank • QB_EXP_EM_MAT_013 MCQ • 1 Mark

Section 1: Engineering Mathematics

Linear Algebra: Matrices & Determinants

Subtopic: Determinant properties

Question Statement:

Let $A$ be a $3 \times 3$ real matrix with $\det(A) = 15$. The determinant of the scalar multiplied matrix $14A$ is:

Options:

  • (A) 41160
  • (B) 210
  • (C) 2940
  • (D) 576240

Answer Key:

A

Step-by-Step Solution & Explanation

For any $n \times n$ square matrix $A$ and a scalar $k$, the determinant scaling property states that: $\det(k A) = k^n \det(A)$ Given that $n = 3$, $k = 14$, and $\det(A) = 15$: $\det(14A) = 14^3 \times 15 = 2744 \times 15 = 41160$ Hence, the correct determinant value is $41160$.
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