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Ex 2.2, 13 (MCQ) - Chapter 2 Class 12 Inverse Trigonometric Functions
Last updated at June 6, 2023 by Teachoo
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
Transcript
Ex 2.2, 13 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
