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  1. Chapter 2 Class 12 Inverse Trigonometric Functions
  2. Serial order wise

Transcript

Ex 2.1, 5 Find the principal value of cos−1 (−1/2) Let y = cos−1 (−1/2) cos y = −1/2 cos y = cos (2π/3). Range of principal value of cos−1 is [0 , 𝜋] Hence, the principal value is 𝟐𝝅/𝟑. Rough We know that cos 60° = 1/2 θ = 60° = 60° × 𝜋/180 = 𝜋/3 Since (−1)/2 is negative Principal value is 𝜋 – θ i.e. π −𝜋/3 = 2𝜋/3

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.