MCQMediumJEE Main 2024 · 30 January, Shift 2Algebra of Matrices

Mathematics Question from JEE Main 2024 · 30 January, Shift 2

Let R=(x000y000z)R = \begin{pmatrix} x & 0 & 0 \\ 0 & y & 0 \\ 0 & 0 & z \end{pmatrix} be a non-zero 3×33 \times 3 matrix, where xsinθ=ysin(θ+2π3)=zsin(θ+4π3)0x\sin\theta = y\sin\left(\theta + \dfrac{2\pi}{3}\right) = z\sin\left(\theta + \dfrac{4\pi}{3}\right) \ne 0, θ(0,2π)\theta \in (0, 2\pi). For a square matrix MM, let trace(M)\operatorname{trace}(M) denote the sum of all the diagonal entries of MM. Then among the statements: (I) Trace(R)=0\operatorname{Trace}(R) = 0 (II) If trace(adj(adj(R)))=0\operatorname{trace}(\operatorname{adj}(\operatorname{adj}(R))) = 0, then RR has exactly one non-zero entry. Which of the following is true?

  • A

    Both (I) and (II) are true

  • B

    Neither (I) nor (II) is true

  • C

    Only (II) is true

  • D

    Only (I) is true

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