Chapter 12 : Troigonometry

Exercise - 25

Evaluate the following:

1.

2. Sec 50⁰ Sin 40⁰ + Cos 40⁰ Cosec 50⁰

3.

4.

5.

6.

7.

8.

9.

10. tan 35⁰ tan 40⁰ tan 45⁰ tan 50⁰ tan 55⁰

11. tan 7⁰ tan 23⁰ tan 60⁰ tan 67⁰ tan 83⁰

12. tan 5⁰ tan 25⁰ tan 30⁰ tan 65⁰ tan 85⁰

13.

14.

15.

16.

17.

18.

19. Express sin 81⁰ + tan 71⁰ in terms of trigonometric ratios of angles between 0⁰ and 45⁰.

20. Express cos 75⁰ + cot 75⁰ in terms of trigonometric ratios of angles between 0⁰ and 45⁰.

21. If where are acute angles, find the value of

22. If A and B are acute angles and sin A = cos B, Prove that A + B = 90⁰.

23. If A, B, C are the interior angles of a triangle ABC, show that show that

24.

25.

26.

Answers

1. 0	2. 2	3. 2	4. 0
5. 0	6. 0	7.1/2	8. 1
9. 1	10. 1	11.	12.
13. 0	14. 2	15. 1	16. 2
17. 2	18. 2	19. cos 90 + cot 190	20. sin 15 0 + tan 15 0
21. 280