Question 4 - Examples - Chapter 3 Class 11 Trigonometric Functions

Last updated at August 2, 2026 by

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 š‘„ = 1/2 Let cos x = cos y Given cos x = 1/2 From (1) and (2) cos y = 1/2 cos y = cos šœ‹/3 y = šœ‹/3 Rough We know that cos 60Ā° = 1/2 So, 60Ā° = 60 Ɨ Ļ€/180 = Ļ€/3 Since cos x = cos y General Solution is x = 2nĻ€ Ā± y where n āˆˆ Z Putting y = šœ‹/3 x = 2nĻ€ Ā±š…/šŸ‘ where n āˆˆ Z

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