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

## (A) b/β(b^2Β - a^2 ) Β Β

## (B) b/a Β

## (C) β(b^2Β - a^2 )/b Β Β

## (D) a/β(b^2Β - a^2 )

Last updated at Oct. 20, 2021 by

Transcript

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

NCERT Exemplar - MCQ

Chapter 8 Class 10 Introduction to Trignometry (Term 1)

Serial order wise

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.