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CSS Pure Mathematics QUESTION #4115
Question 1
Consider vectors $\mathbf{a} = (1, 2, 3)$, $\mathbf{b} = (2, 5, 7)$, $\mathbf{c} = (1, 3, 5)$ in $\mathbb{R}^3$. Compute $\det \begin{pmatrix} 1 & 2 & 1 \ 2 & 5 & 3 \ 3 & 7 & 5 \end{pmatrix}$. What does this indicate?
  • Determinant is $0$, vectors are linearly dependent
  • Determinant is $1$, vectors are linearly independent✔️
  • Determinant is $-1$, vectors are linearly independent
  • Determinant is $2$, vectors are linearly dependent
Correct Answer Explanation
$\det = 1(25-21) - 2(10-9) + 1(14-15) = 4 - 2 - 1 = 1 \neq 0$. Since determinant is non-zero, the vectors are linearly independent.