1. The value of (cos 0° × cos 1° × cos 2° × cos 3° × … × cos 90°) is 1.

2. What is the value of (cos 0° × cos 1° × cos 2° × … × cos 90°)?

3. The value of sin 0° × sin 1° × sin 1° × sin 2° … × sin 90° is 1.

4. The value of \( \cos 0° × \cos 1° × \cos 2° × \cos 3° × \ldots × \cos 90° \) is 1.

5. **"cos 0° × cos 1° × cos 2° × ... × cos 90° = —"**

6. If tan 2θ × tan 4θ = 1, then what is the value of sin 2θ?

7. In triangle ABC, ∠B = 90°, and BC = \(\sqrt{3}\) × AB. What is the value of \(\sin C\)?

(a) \(\cfrac{1}{2}\) (b) 1 (c) \(\cfrac{1}{\sqrt3}\) (d) \(\sqrt3\)

8. A hollow cube is made using copper sheets that are 1.5 cm thick, with an external edge length of 20 cm. After melting the cube, how many solid cuboids measuring 7 cm × 3 cm × 1 cm can be made from it?

(a) 200 (b) 220 (c) 100 (d) 147

9. Given that \( \tan 4θ × \tan 6θ = 1 \) and \( 6θ \) is a positive acute angle, find the value of \( \tan 5θ \).

10. The value of \((\cos 0° × \cos 1° × \cos 2° × \cos 3° × ... × \cos 90°)\) is \(1\).