Question 4 - Examples - Chapter 3 Class 11 Trigonometric Functions

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Example 21 - Solve cos x = 1/2 - Trigonometric Functions CBSE

Example 21 - Chapter 3 Class 11 Trigonometric Functions - Part 2

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Question 4 Solve cos 𝑥 = 1/2 Let cos x = cos y Given cos x = 1/2 From (1) and (2) cos y = 1/2 cos y = cos 𝜋/3 y = 𝜋/3 Rough We know that cos 60° = 1/2 So, 60° = 60 × π/180 = π/3 Since cos x = cos y General Solution is x = 2nπ ± y where n ∈ Z Putting y = 𝜋/3 x = 2nπ ±𝝅/𝟑 where n ∈ Z

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