1. If ΔABC is right angled at C, then the value of cos (A + B) is

2.

3. sin (45° + θ) – cos (45° – θ) is equal to

4.

5. The value of (tanl° tan2° tan3°… tan89°) is

6. If sinα = 1/2 and cosβ = 1/2 then the value of (α + β) is

7. If sin A = 1/2 then the value of cot A is

8. tan θ + tan θ = sec θ – sec θ.

9. If cos(α+ β) = 0, then sin (α – β) can be reduced to

10. If a pole 6 m high casts a shadow 2√3 m long on the ground, then the Sun’s elevation is

11. If cos A = 4/5 , then the value of tan A is

12. If sin A + sin² A = 1, then the value of (cos² A + cos⁴ A) is

13. The value of the expression cosec (75° + 0) – sec (15° – 0) – tan (55° + 0) + cot (35° – 0) is

14. (tanθ + 2) (2 tanθ + 1) = 5 tanθ + sec² θ

15. If sinθ – cosθ= 0, then the value of (sin θ + cos θ) is

16. The value of the expression (sin 80° – cos 80°) is negative.

17. If cos 9α = sin α and 9α < 90° ,then the value of tan 5α is

18. If sinθ = a/b , then cosθ is equal to

19. tan 47⁰/cot 43⁰ = 1

20. The value of the expression (cos 23° – sin 67°) is positive.