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The maximum value of Δ=∣1sin⁡θ1−sin⁡θ1sin⁡θ−1−sin⁡θ1∣\Delta = \begin{vmatrix}1 & \sin\theta & 1\\ -\sin\theta & 1 & \sin\theta\\ -1 & -\sin\theta & 1\end{vmatrix} is (θ\theta is real number)

Solution

✅ Correct Option: 3

Let s=sin⁡θs=\sin\theta. Expanding along the first row:

Δ=(1+s2)−s(−s+s)+(s2+1)=2+2s2\Delta = (1+s^2)-s(-s+s)+(s^2+1) = 2+2s^2.

Since s2≤1s^2\leq 1, the maximum is 2+2=42+2 = 4 (at θ=±π2\theta = \pm\frac{\pi}{2}).

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