Question 7 - NCERT Exemplar - MCQ - Chapter 8 Class 10 Introduction to Trignometry

Last updated at December 16, 2024 by Teachoo

Given that sin θ = a/b, then cos θ is equal to

(A) b/√(b^2 - a^2 )

(B) b/a

(C) √(b^2 - a^2 )/b

(D) a/√(b^2 - a^2 )

MCQ - Class 10 Boards - Given that sin θ = a/b, then cos θ is equal - NCERT Exemplar - MCQ

part 2 - Question 7 - NCERT Exemplar - MCQ - Serial order wise - Chapter 8 Class 10 Introduction to Trignometry

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Transcript

Question 7 Given that sin θ = 𝑎/𝑏, then cos θ is equal to (A) 𝑏/√(𝑏^2 − 𝑎^2 ) (B) 𝑏/𝑎 (C) √(𝑏^2 − 𝑎^2 )/𝑏 (D) 𝑎/√(𝑏^2 − 𝑎^2 ) Now, cos2 θ = 1 − sin2 θ Putting sin θ = 𝑎/𝑏 cos2 θ = 1−(𝑎/𝑏)^2 cos2 θ = 1−𝑎^2/𝑏^2 cos2 θ = (𝒃^𝟐 − 𝒂^𝟐)/𝒃^𝟐 Taking square root cos θ = ± √((𝑏^2 − 𝑎^2)/𝑏^2 ) cos θ = ± √(𝑏^2 − 𝑎^2 )/𝑏 Since only positive values are given in options cos θ = √(𝒃^𝟐 − 𝒂^𝟐 )/𝒃 So, the correct answer is (C)

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo

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