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

Last updated at Dec. 16, 2024 by Teachoo

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

(A) 1/√3   (B) √3   (C) 1  (D) 0

Transcript

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)
  1. Chapter 8 Class 10 Introduction to Trignometry
  2. Serial order wise

    3. NCERT Exemplar - MCQ

    sin 90 - θ, cos 90 - θ formula →
sin 90 - θ, cos 90 - θ formula →
Chapter 8 Class 10 Introduction to Trignometry
Serial order wise

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Davneet Singh

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