Question 4 - NCERT Exemplar - MCQ - Chapter 8 Class 10 Introduction to Trignometry

Last updated at Dec. 16, 2024 by

If cos A = 4/5 , then the value of tan A is

(A) 3/5  (B) 3/4    (C) 4/3  (D) 5/3

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Question 4 If cos A = 4/5 , then the value of tan A is (A) 3/5 (B) 3/4 (C) 4/3 (D) 5/3 Since cos A = 4/5 ∴ sec A = 𝟓/𝟒 Now, 1 + tan2 A = sec2 A Putting values 1 + tan2 A = (5/4)^2 1 + tan2 A = 25/16 tan2 A = 25/16−1 tan2 A = (25 − 16)/16 tan2 A = 9/16 tan2 A = (𝟑/𝟒)^𝟐 Removing square tan A = ± 3/4 Since only positive values are given in options tan A = 𝟑/𝟒 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