If $\theta \in[-2 \pi, 2 \pi]$, then the number of solutions of $2 \sqrt{2} \cos ^2 \theta+(2-\sqrt{6}) \cos…

If $\theta \in[-2 \pi, 2 \pi]$, then the number of solutions of $2 \sqrt{2} \cos ^2 \theta+(2-\sqrt{6}) \cos \theta-\sqrt{3}=0$, is equal to:
  1. 12
  2. 6
  3. 8
  4. 10

Solution

$\begin{aligned} & 2 \sqrt{2} \cos ^2 \theta+2 \cos \theta-\sqrt{6} \cos \theta-\sqrt{3}=0 \\ & (2 \cos \theta-\sqrt{3})(\sqrt{2} \cos \theta+1)=0 \\ & \cos \theta=\frac{\sqrt{3}}{2}, \frac{-1}{\sqrt{2}}\end{aligned}$
Number of solution $=8$ *

Asked in: JEE Main 2025 (02 Apr Shift 1)

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