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Finding 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
Misc 1
Ex 2.2, 14 (MCQ) Important
Ex 2.2, 15 (MCQ) You are here
Ex 2.1, 12 Important
Ex 2.1, 14 (MCQ) Important
Ex 2.1, 11 Important
Last updated at May 29, 2023 by Teachoo
Ex 2.2, 21 Find value of : tan−1 √3 – cot−1 (−√3) Finding tan−1 √𝟑 Let y = tan−1 √3 tan y = √3 tan y = tan (𝝅/𝟑) ∴ y = 𝝅/𝟑 Since range of tan-1 is ((−π)/2,π/2) Hence, Principal Value is 𝝅/𝟑 (Since tan 𝜋/3 = √3) ∴ tan−1 √3 = π/3 Finding cot−1 (−√𝟑) Let x = cot−1 (√3) x = 𝜋 − cot−1 (√3) x = 𝜋 − 𝛑/𝟔 x = 𝟓𝛑/𝟔 We know that cot−1 (−x) = 𝜋 − cot −1 x Since cot 𝜋/6 = √3 𝜋/3 = cot−1 (√3) Since range of cot−1 is (0, π) Hence, Principal Value is 𝟓𝛑/𝟔 ∴ cot−1 (−√3) = 5π/6 Hence, tan−1 √3 = π/3 & cot−1 (−√3) = 5π/6 Now calculating tan−1 √𝟑 – cot−1 (−√𝟑) = π/3 − 5π/6 = (2𝜋 − 5π)/6 = (−3π)/6 = (−𝝅)/𝟐 Hence, option (B) is correct