Ifย  y = log ((1 - x 2 )/(1 + x 2 )),then dy/dx is equal to

(A) ใ€–4x 3 /(1-x 4 )ย 

(B) (-4x)/(1-x 4 )

(C) 1/(4-x 4 )ย 

(D) (-4x 3 )/(1-x 4 )

[MCQ] If y = log ((1 โˆ’ ๐‘ฅ^2)/(1 + ๐‘ฅ^2 )), then ๐‘‘๐‘ฆ/๐‘‘๐‘ฅ is equal to - NCERT Exemplar - MCQs

part 2 - Question 19 - NCERT Exemplar - MCQs - Serial order wise - Chapter 5 Class 12 Continuity and Differentiability

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Question 19 If y = log ((1 โˆ’ ๐‘ฅ^2)/(1 + ๐‘ฅ^2 )),then ๐‘‘๐‘ฆ/๐‘‘๐‘ฅ is equal to (A) ใ€–4๐‘ฅใ€—^3/(1โˆ’๐‘ฅ^4 ) (B) (โˆ’4๐‘ฅ)/(1โˆ’๐‘ฅ^4 ) (C) 1/(4โˆ’๐‘ฅ^4 ) (D) (โˆ’4๐‘ฅ^3)/(1โˆ’๐‘ฅ^4 ) y=log((1 โˆ’ ๐‘ฅ^2)/(1 +ใ€– ๐‘ฅใ€—^2 )) ๐ฒ=๐ฅ๐จ๐ (๐Ÿโˆ’๐’™^๐Ÿ )โˆ’๐ฅ๐จ๐ โกใ€–(๐Ÿ+๐’™^๐Ÿ)ใ€— Differentiating wrt ๐‘ฅ ๐’…๐’š/๐’…๐’™=๐‘‘(log(1 โˆ’ ๐‘ฅ^2 ) โˆ’ logโกใ€–(1 + ๐‘ฅ^2)ใ€— )/๐‘‘๐‘ฅ =๐‘‘(log(1 โˆ’ ๐‘ฅ^2 ))/๐‘‘๐‘ฅโˆ’๐‘‘(log(1 + ๐‘ฅ^2 ))/๐‘‘๐‘ฅ =๐Ÿ/((๐Ÿ โˆ’ ๐’™^๐Ÿ ) ) ๐’…(๐Ÿ โˆ’ ๐’™^๐Ÿ )/๐’…๐’™โˆ’๐Ÿ/((๐Ÿ + ๐’™^๐Ÿ ) ) ๐’…(๐Ÿ + ๐’™^๐Ÿ )/๐’…๐’™ =1/((1 โˆ’ ๐‘ฅ^2 ) )(0โˆ’2๐‘ฅ)โˆ’1/((1 + ๐‘ฅ^2 ) ) (0+2๐‘ฅ) =(โˆ’2๐‘ฅ)/((1 โˆ’ ๐‘ฅ^2 ) )โˆ’2๐‘ฅ/((1 + ๐‘ฅ^2 ) ) =โˆ’2๐‘ฅ(1/((1 โˆ’ใ€– ๐‘ฅใ€—^2 ) )+1/((1 +ใ€– ๐‘ฅใ€—^2 ) )) =โˆ’2๐‘ฅ((1 + ๐‘ฅ^2 + 1 โˆ’ใ€– ๐‘ฅใ€—^2)/(1 โˆ’ ๐‘ฅ^2 )(1 + ๐‘ฅ^2 ) ) =โˆ’2๐‘ฅ(2/(1 โˆ’ใ€– ๐‘ฅใ€—^2 )(1 + ๐‘ฅ^2 ) ) =(โˆ’๐Ÿ’๐’™)/(๐Ÿ โˆ’ ๐’™^๐Ÿ’ ) So, the correct answer is (B)

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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 and Computer Science at Teachoo