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Trigonometry ( 11 to 15 ):
APTITUDE QUESTIONS (TRIGONOMETRY):
11. If sin θ = 2ab / a2+b2 , then the value of tan is equal to
A) a2–b2 / 2ab
B) 2ab / a2-b2
C) a2–b2 / a2+b2
D) a2+b2 / a2-b2
E) None of these
View Answer
Answer: option (B)
Explanation:
12. How many degrees are there in an angle which equals two-third of its complement?
A) 36º
B) 45º
C) 48º
D) 60º
E) None of these
View Answer
Answer: option (A)
Explanation:
Given, α + β = 90 …(i)
By given condition,
β = (2/3) α
∴ β = 2/3 (90º – β) [from eq. i]
=> β = 60º β => (2/3) β = 36º
13. If sin B = 1/2 , then 3 cos B – 4 cos3 B is equal to
A) 1
B) 3/4
C) 0
D) 2 (1/2)
E) None of these
View Answer
Answer: option (C)
Explanation:
14. If sec α = 5/4 , then tan α / 1+tanα is equal to
A) sin α/sec α
B) sin α cos α
C) cos 2α
D) tan α
E) None of these
View Answer
Answer: option (B)
Explanation:
tan α / 1+tan2 α = cos α / sec2 α
=sin α / cos α * (cos2 α / 1)= sin α . cos α
15. What is the value of cos 1º cos 2º cos 3º ….cos 90º?
A) 1/2
B) 0
C) 1
D) 2
E) None of these
View Answer
Answer: option (B)
Explanation:
∵ cos 90º = 0
∴ cos 1º cos 2º cos 3º ….cos 90º = 0