## MCQ Questions for Class 10 Maths: Ch 8 Introduction to Trigonometry

1. If x and y are complementary angles, then
(a) sin x = sin y
(b) tan x = tan y
(c) cos x = cos y
(d) sec x = cosec y
► (d) sec x = cosec y

2. sin 2B = 2 sin B is true when B is equal to
(a) 90°
(b) 60°
(c) 30°
(d) 0°
► (d) 0°

3. If Î”ABC is right angled at C, then the value of cos (A + B) is
(a) 0
(b) 1
(c) 1/2
(d) √3/2
► (a) 0

4. If sin Î¸ + sin² Î¸ = 1, then cos² Î¸ + cos4 Î¸ = ____
(a) -1
(b) 0
(c) 1
(d) 2
► (c) 1

5. If x = a cos 0 and y = b sin 0, then b2x2 + a2y2 =
(a) ab
(b) b2 + a2
(c) a2b2
(d) a4b4
► (c) a2b2

6. If cos A + cos2 A = 1, then sin2 A + sin4 A is
(a) -1
(b) 0
(c) 1
(d) 2
► (c) 1

7. The value of cos Î¸ cos(90° - Î¸) – sin Î¸ sin (90° - Î¸) is:
(a) 1
(b) 0
(c) -1
(d) 2
► (b) 0

8. If tan 2A = cot (A – 18°), then the value of A is
(a) 24°
(b) 18°
(c) 27°
(d) 36°
► (d) 36°

9. If tan Î¸ = 12/5, then 1+sinÎ¸/1-sinÎ¸  is equal to
(a) 24
(b) 12/13
(c) 25
(d) 9
► (c) 25

10. If sin Î¸ − cos Î¸ = 0, vthen the value of Î¸ is
(a) 90°
(b) 30°
(c) 45°
(d) 60°
► (c) 45°

11. Ratios of sides of a right triangle with respect to its acute angles are known as
(a) trigonometric identities
(b) trigonometry
(c) trigonometric ratios of the angles
(d) none of these
► (c) trigonometric ratios of the angles

12. Out of the following options, the two angles that are together classified as complementary angles are
(a) 120° and 60°
(b) 50° and 30°
(c) 65° and 25°
(d) 70° and 30°
► (c) 65° and 25°

13. (1 + tanÎ¸ + secÎ¸) (1 + cotÎ¸ - cosecÎ¸) is equal to
(a) 0
(b) 1
(c) 2
(d) -1
► (c) 2

14. If √3tanÎ¸ = 3sinÎ¸, then the value of sin2Î¸−cos2Î¸ is
(a) 0
(b) 1
(c) 1/2
(d) 1/3
► (d) 1/3

15. 7 sin2Î¸ + 3 cos2Î¸ = 4 then :
(a) tan Î¸ = 1/√2
(b) tan Î¸ = 1/2
(c) tan Î¸ = 1/3
(d) tan Î¸ = 1/√3
► (d) tan Î¸ = 1/√3

16. If sin A = 1/2,  then the value of cot A is
(a) √3
(b) 1/√3
(c) √3/2
(d) 1
► (a) √3

17. If cos 9Î± = sin Î± and 9Î± < 90°, then the value of tan 5Î± is
(a) 1/√3
(b) √3
(c) 1
(d) 0
► (c) 1

18. Given that sin A=1/2 and cos B=1/√2 then the value of (A + B) is:
(a) 30°
(b) 45°
(c) 75°
(d) 15°
► (c) 75°

19. If sin x + cosec x = 2, then sin19x + cosec20x =
(a) 219
(b) 220
(c) 2
(d) 239
►(c) 2

20. In right triangle ABC, right angled at C, if tan A = 1, then the value of 2 sin A cos A is
(a) 0
(b) 1
(c) – 1
(d) 2
► (b) 1

21. If cos (40° + A) = sin 30°, the value of A is:​
(a) 60°
(b) 20°
(c) 40°
(d) 30°
► (b) 20°

22. If 0° < Î¸ < 90°, then sec 0 is
(a) >1
(b) < 1
(c) =1
(d) 0
► (a) >1

23. If cos (Î± + Î²) = 0, then sin (Î± – Î²) can be reduced to
(a) cos Î²
(b) cos 2Î²
(c) sin Î±
(d) sin 2Î±
► (b) cos 2Î²

24. sin (45° + Î¸) – cos (45° – Î¸) is equal to
(a) 2 cos Î¸
(b) 0
(c) 2 sin Î¸
(d) 1
► (b) 0