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

Last updated at Dec. 16, 2024 by

If cos (α + β) = 0, then sin (α – β) can be reduced to

(A) cos β   (B) cos 2β   (C) sin α   (D) sin 2α

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Question 8 If cos (α + β) = 0, then sin (α – β) can be reduced to (A) cos β (B) cos 2β (C) sin α (D) sin 2α Given that cos (α + β) = 0 cos (α + β) = cos 90° Comparing angles α + β = 90° α = 90° − β Now, sin (α – β) = sin (90° − β − β) = sin (90° − 2β) Using cos A = sin (90° − A) = cos 2β So, the correct answer is (B)

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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