If cos 9α = sin α and 9α < 90° , then the value of tan 5α is

(A) 1/√3   (B) √3   (C) 1  (D) 0

NCERT Exemplar (MCQ) - If cos 9α = sin α and 9α < 90° , then value of - NCERT Exemplar - MCQ

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

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Question 10 If cos 9α = sin α and 9α < 90° , then the value of tan 5α is (A) 1/√3 (B) √3 (C) 1 (D) 0 Given cos 9α = sin α cos 9α = cos (90° − α) Comparing angles 9α = 90° − α 9α + α = 90° 10α = 90° α = (90° )/(10° ) α = 9° Now, tan 5α = tan (5 × 9°) = tan 45° = 1 So, the correct answer is (C)

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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