Derivatives · Exponential & Logarithmic

Derivative of ln(x)

ddx[lnx]=1x\frac{d}{dx}[\ln x] = \frac{1}{x}

The derivative of the natural logarithm is 1/x.

Conditions. x > 0.

Worked examples

Find d/dx[ln(x²)].
  1. Chain rule: (1/x²) · 2x = 2/x. Or simplify first: ln(x²) = 2 ln x, so d/dx = 2/x.

Answer: 2/x

Find d/dx[x ln x].
  1. Product rule: (1)(ln x) + (x)(1/x) = ln x + 1

Answer: ln x + 1

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