If $A = \begin{bmatrix} 0 & \sin \alpha \\ \sin \alpha & 0 \end{bmatrix}$ and $\det(A^{2} - \frac{1}{2}I) =…

If $A = \begin{bmatrix} 0 & \sin \alpha \\ \sin \alpha & 0 \end{bmatrix}$ and $\det(A^{2} - \frac{1}{2}I) = 0$, then a possible value of $\alpha$ is
  1. π2
  2. π3
  3. π4
  4. π6

Solution

A2=sin2αI

So, A2-I2=sin2α-122=0

sinα=12

α=π4 

Asked in: JEE Main 2021 (17 Mar Shift 1)

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