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  1. Chapter 2 Class 12 Inverse Trigonometric Functions
  2. Serial order wise

Transcript

Ex 2.2, 2 3cosโˆ’1 ๐‘ฅ = cosโˆ’1 (4๐‘ฅ^3โˆ’ 3๐‘ฅ ), ๐‘ฅโˆˆ [1/2,1] Solving R.H.S cos^(โˆ’1) (4๐‘ฅ^3โˆ’ 3๐‘ฅ ) Putting x = cos ๐œƒ = cos^(โˆ’1) (4 ใ€–"(cos ๐œƒ)" ใ€—^3โˆ’ 3cos ๐œƒ) = cos^(โˆ’1) (4 ใ€–"cos" ใ€—^๐Ÿ‘๐œƒ โˆ’ 3cos ๐œƒ) = cos^(โˆ’1) (cos 3๐œƒ ) = 3๐œƒ (cos 3x = 4 cos^3x โˆ’ 3 cos x) (cos^(โˆ’1) (cos x) = x ) Now, x = cos ๐œƒ โˆด cos^(โˆ’1) (x) = ๐œƒ = 3 cos^(โˆ’1) x = L.H.S Hence, proved.

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.