Example 26 - Find derivative of f(x) = sin-1 x - Class 12 - Examples


  1. Chapter 5 Class 12 Continuity and Differentiability
  2. Concept wise


Example 26-Find the derivative of f given by 𝑓 (π‘₯)=〖𝑠𝑖𝑛〗^(βˆ’1) π‘₯ assuming it exists. 𝑓 (π‘₯)=〖𝑠𝑖𝑛〗^(βˆ’1) π‘₯ Let 𝑦= 〖𝑠𝑖𝑛〗^(βˆ’1) π‘₯ sin⁑〖𝑦=π‘₯γ€— π‘₯=sin⁑〖𝑦 γ€— Differentiating both sides 𝑀.π‘Ÿ.𝑑.π‘₯ 𝑑π‘₯/𝑑π‘₯ = (𝑑 (sin⁑𝑦 ))/𝑑π‘₯ 1 = (𝑑 (sin⁑𝑦 ))/𝑑π‘₯ Γ— 𝑑𝑦/𝑑𝑦 1 = (𝑑 (sin⁑𝑦 ))/𝑑𝑦 Γ— 𝑑𝑦/𝑑π‘₯ 1 = cos⁑𝑦 𝑑𝑦/𝑑π‘₯ 1/cos⁑𝑦 =𝑑𝑦/𝑑π‘₯ 𝑑𝑦/𝑑π‘₯ = 1/π’„π’π’”β‘π’š 𝑑𝑦/𝑑π‘₯= 1/√(𝟏 βˆ’ γ€–π’”π’Šπ’γ€—^𝟐 π’š) "We know that" 〖𝑠𝑖𝑛〗^2 πœƒ+γ€–π‘π‘œπ‘ γ€—^2 πœƒ=1 γ€–π‘π‘œπ‘ γ€—^2=1βˆ’γ€–π‘ π‘–π‘›γ€—^2 πœƒ cosβ‘πœƒ=√(1βˆ’γ€–π‘ π‘–π‘›γ€—^2 πœƒ) " " Putting 𝑠𝑖𝑛⁑〖𝑦=π‘₯γ€— 𝑑𝑦/𝑑π‘₯= 1/√(1 βˆ’ 𝒙^𝟐 ) As 𝑦 = 〖𝑠𝑖𝑛〗^(βˆ’1) π‘₯ So, 𝑠𝑖𝑛⁑𝑦 = π‘₯ Hence, (𝒅(γ€–π’”π’Šπ’γ€—^(βˆ’πŸ) 𝒙" " ))/𝒅𝒙 = 𝟏/√(𝟏 βˆ’ 𝒙^𝟐 )

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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.