Trigonometry (Railway Maths) (Part – IV)

Total Questions: 50

31. Find the value of sin78° + cos132° : [RRB NTPC 15/02/2021 (Evening) ]

Correct Answer: (a) sin18°
Solution:

32. The value of sin1°sin2°sin3°……sin180°sin196° is : [RRB NTPC 16/02/2021 (Morning) ]

Correct Answer: (c) 0
Solution:

33. if tanθ = -12/5, then the value of sinθ is: [RRB NTPC 16/02/2021 (Evening) ]

Correct Answer: (c) -12/13
Solution:

34. If cosθ = cosα then general solution for θ is: [RRB NTPC 16/02/2021 (Evening) ]

Correct Answer: (a)
Solution:

35. If sinθ - cosθ = √3/2, then find the value positive value of sinθ + cosθ. [RRB NTPC 17/02/2021 (Evening) ]

Correct Answer: (d) √5/2
Solution:

36. If cosA + secA = 5/2 and A is a acute angle, then sin A + cosecA is equal to: [RRB NTPC 22/02/2021 (Evening) ]

Correct Answer: (c) 7/ 2√3
Solution:

37. If secθ + tanθ / secθ - tanθ = 5/3, then the value of sinθ is: [RRB NTPC 23/02/2021 (Morning) ]

Correct Answer: (d) 1/4
Solution:

38. Find the answer of given question? [RRB NTPC 23/02/2021 (Morning) ]

Which of the following is a simplified form of the expression :
sinAcosA(tanA - cotA),where (0° < A < 90°)?

Correct Answer: (b) 2sin²A - 1
Solution:

39. If sin2A = cos75° , then the smallest positive value of A is : [RRB NTPC 27/02/2021 (Morning) ]

Correct Answer: (a) 7.5°
Solution:

sin2A = cos 75°
⇒ sin 2A = sin15° ⇒ 2A = 15° ⇒ A = 7.5°

40. If A + B = 45°, then (1 + tanA) (1 + tanB) = ? [RRB NTPC 27/02/2021 (Morning) ]

Correct Answer: (c) 2
Solution: