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Finding principal value

Principal Value

Example 1 Important

Ex 2.1, 1

Ex 2.1, 3

Ex 2.1, 10 Important

Ex 2.1, 2

Ex 2.1, 5 Important

Ex 2.1, 9

Ex 2.1, 7 Important

Ex 2.1, 4 Important

Ex 2.1, 6

Ex 2.1, 8 Important

Example 2

Ex 2.2, 10

Example 6 Important

Ex 2.2, 8

Ex 2.2, 11

Misc 2 Important

Ex 2.2, 13 (MCQ) Important You are here

Misc 1

Ex 2.2, 14 (MCQ) Important

Ex 2.2, 15 (MCQ)

Ex 2.1, 12 Important

Ex 2.1, 14 (MCQ) Important

Ex 2.1, 11 Important

Chapter 2 Class 12 Inverse Trigonometric Functions

Concept wise

Last updated at May 29, 2023 by Teachoo

Ex 2.2, 19 Find the values of cos−1(cos 7π/6) is equal to (A) 7π/6 (B) 5𝜋/6 (C) 𝜋/3 (D) 𝜋/6 Let y = cos−1 (cos 7π/6) cos y = cos (7π/6) cos y = cos (210°) Since Range of of cos−1 is [0, π] i.e. [0° ,180°] Hence, y = 210° not possible Now, cos y = cos (210°) cos y = cos (360° – 150°) cos y = cos (150°) cos y = cos (𝟓𝝅/𝟔) Hence, y = 𝟓𝝅/𝟔 Which is in the range of principal value of cos-1 i.e. [0, π] Hence , cos −1 (cos 7π/6) = 5𝜋/6 Thus, option (B) is correct (As cos (360° – θ) = cos θ)