চিত্র থেকে-

1. cotθ এর মান $2 + \sqrt{3}$  

2. OA এর মান $– 5 \left ( \sqrt{6} + \sqrt{2} \right )$  

3. cosec2θ এর মান 2

নিচের কোনটি সঠিক?

$\begin{aligned} \sin \theta & =\frac{A B}{O A} \\ \text { or, } O A & =\frac{A B}{\sin \theta}=\frac{A B}{-\sin \left(270^{\circ}-195^{\circ}\right)} \\ & =\frac{-5}{-\sin 75^{\circ}}=\frac{5}{\sin \left(45^{\circ}+30^{\circ}\right)} \\ & =\frac{5}{\sin 45^{\circ} \cos 30^{\circ}+\cos 45^{\circ} \sin 30^{\circ}}\end{aligned}$

$\begin{array}{l}=\frac{5}{\frac{1}{\sqrt{2}} \times \frac{\sqrt{3}}{2}+\frac{1}{\sqrt{2}} \times \frac{1}{2}} \\ =\frac{5}{\frac{\sqrt{3}+1}{2 \sqrt{2}}}=\frac{10 \sqrt{2}}{\sqrt{3}+1} \\ =\frac{10 \sqrt{2}(\sqrt{3}-1)}{3-1} \\ =5(\sqrt{6}-\sqrt{2})\end{array}$

$\therefore$ ii সঠিক নয়।