cot²θ-2√2 cosecθ+3=0, হলে θ এর মান কত?

$\begin{aligned} & \cot ^{2} \theta-2 \sqrt{2} \operatorname{cosec} \theta+3=0 \\ \Rightarrow & \operatorname{cosec}^{2} \theta-2 \sqrt{2} \operatorname{cosec} \theta+2=0 \\ \Rightarrow & (\operatorname{cosec} \theta-\sqrt{2})^{2}=0 \\ \Rightarrow & \operatorname{cosec} \theta=\sqrt{2} \\ \Rightarrow & \sin \theta=\frac{1}{\sqrt{2}} \\ \therefore & \theta=45^{\circ} \end{aligned}$

আবার

$\begin{array}{l} \text { } \sin \theta=\sin \frac{\pi}{4} \\ \Rightarrow \sin \theta=\sin \left(180^{\circ}-45^{\circ}\right) \\ \therefore \theta=135^{\circ} \end{array}$