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Question

Consider the following statements:

I. \(\dfrac{d}{dx}\ln|x| = -\dfrac{1}{x}\) if \(x < 0\)

II. \(\dfrac{d}{dx}\ln|x| = \dfrac{1}{x}\) if \(x > 0\)

Which of the statements given above is/are correct?

This question was previously asked in
NDA 2 2026 GAT Question Paper (13-Sep-2026)
The correct answer is

II only

The correct derivative of \(\ln|x|\) is \(\dfrac{1}{x}\) for all \(x \neq 0\), which can be verified by writing \(\ln|x| = \ln(-x)\) for \(x < 0\) and differentiating using the chain rule to get \(\dfrac{-1}{-x} = \dfrac{1}{x}\). So statement I, which claims the derivative is \(-\dfrac{1}{x}\) for \(x < 0\), is incorrect, while statement II, which gives \(\dfrac{1}{x}\) for \(x > 0\), is correct. Hence only statement II is correct.

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Important Questions from Evaluation of derivatives

  1. Differentiate {-log (log x), x > 1} with respect to x

  2. Find the derivation of f(x) = 1/x2

  3. The derivative of the function f(x) = -3x2 + 6x - 4 is given by:
  4. Differential coefficient of log10 x with respect to logx 10 is

  5. The derivatives of (x3 + ex + 3x + cot x) with respect to x is

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