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Question 16 (OR 2 nd question)

If y = log⁡ (1 + 2t + t 4 ), x = tan -1 ⁡t, find d 2 y/dx 2


Transcript

Question 16 (OR 2nd question) If y = log⁡〖(1+2𝑡^2+𝑡^4)〗, x = tan^(−1)⁡𝑡, find (𝑑^2 𝑦)/(𝑑𝑥^2 ) Finding 𝒅𝒚/𝒅𝒕 y = log⁡〖(1+2𝑡^2+𝑡^4)〗 𝑑𝑦/𝑑𝑡 = 1/((1 + 2𝑡^2 + 𝑡^4 ) ) × 𝑑(1 + 2𝑡^2 + 𝑡^4 )/𝑑𝑡 𝑑𝑦/𝑑𝑡 = ((4𝑡^3 + 4𝑡))/((1 + 2𝑡^2 + 𝑡^4 ) ) 𝑑𝑦/𝑑𝑡 = (4𝑡(𝑡^2 + 1))/(((𝑡^2 )^2 + 2𝑡^2 + 1^2 ) ) 𝑑𝑦/𝑑𝑡 = (4𝑡(𝑡^2 + 1))/(𝑡^2 + 1)^2 𝑑𝑦/𝑑𝑡 = 4𝑡/((𝑡^2 + 1) ) Finding 𝒅𝒙/𝒅𝒕 x = tan^(−1)⁡𝑡 𝑑𝑥/𝑑𝑡 = 1/(1 + 𝑡^2 ) Now, 𝑑𝑦/𝑑𝑥 = (𝑑𝑦/𝑑𝑡)/(𝑑𝑥/𝑑𝑡) 𝑑𝑦/𝑑𝑥 = (4𝑡/((𝑡^2 + 1) ))/(1/(1 + 𝑡^2 )) 𝑑𝑦/𝑑𝑥 = 4𝑡/((𝑡^2 + 1) )×((1 + 𝑡^2))/1 𝑑𝑦/𝑑𝑥 = 4t Now, (𝑑^2 𝑦)/(𝑑𝑥^2 ) = (𝑑(4𝑡))/𝑑𝑥 = (𝑑(4𝑡))/𝑑𝑥 × 𝑑𝑡/𝑑𝑡 = (𝑑(4𝑡))/𝑑𝑡 × 𝑑𝑡/𝑑𝑥 = 4 × 𝑑𝑡/𝑑𝑥 = 4 × 1/(𝑑𝑥/𝑑𝑡) = 4 (1 + t2) As 𝑑𝑥/𝑑𝑡 = 1/(1 + 𝑡^2 ) 𝑑𝑡/𝑑𝑥 = (1 + t2)

  1. Class 12
  2. Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

About the Author

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 and Computer Science at Teachoo