Ex 2.2, 10 Find the values of sin-1(sin⁡〖2π/3〗 ) Let y = sin-1 (sin 2𝜋/3) sin y = sin 2𝜋/3 sin y = sin (120°) But, Range of sin-1 is [(−π)/2, π/2] i.e. [-90° ,90° ] Hence, y = 120° not possible Now, sin y = sin (120°) sin y = sin (180° – 60°) sin y = sin (60°) sin y = sin (60 × 𝜋/180) sin y = sin 𝜋/3 Hence, y = 𝝅/𝟑 Since this is in range of sin-1 i.e. [(−π)/2, π/2] Hence, sin-1(sin 𝟐𝛑/𝟑) = 𝝅/𝟑

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.