Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class
Miscellaneous
Misc 2 Important
Misc 3
Misc 4 Important
Misc 5
Misc 6
Misc 7 Important
Misc 8 Important
Misc 9 Important
Misc 10 Important
Misc 11 Important
Misc 12
Misc 13 (MCQ) Important
Misc 14 (MCQ) Important
Question 1 Important Deleted for CBSE Board 2024 Exams
Question 2 Important Deleted for CBSE Board 2024 Exams
Question 3 (MCQ) Deleted for CBSE Board 2024 Exams
Miscellaneous
Last updated at June 6, 2023 by Teachoo
Misc 1 Find the value of cos-1 (cos〖13π/6〗 ) Let y = cos-1 (cos〖13π/6〗 ) cos y = cos 13π/6 cos y = cos (390°) But, Range of cos−1 is [0, π] i.e. [0°, 180°] Hence, y = 390° not possible Now, cos y = cos (390°) cos y = cos (360° + 30°) cos y = cos (30°) cos y = cos (𝜋/6) ∴ y = 𝝅/𝟔 Which is in the range of cos-1 i.e. [0, π] Hence , cos −1 (cos 13π/6 " " ) = 𝝅/𝟔