Derivative of
The derivative of is .
f(x) =
Type any function of x; the derivative is computed symbolically in your browser.
How to work it out
- 1
We differentiate with respect to x. The rule that applies is the quotient rule.
- 2
Quotient rule: . Let and .
- 3
Differentiate each piece:
- 4
Put them in the rule:
- 5
Simplify:
- 6
Differentiating once more gives the second derivative, which tells you about curvature:
LaTeX source of the formulas on this page
\[ \frac{d}{dx}\left[\frac{\ln\left(x\right)}{\frac{1}{x}}\right] = \frac{\frac{\frac{1}{x}}{x} - \ln\left(x\right) \frac{-1}{x^{2}}}{\frac{1}{x}^{2}} \]
\[ f(x) = \frac{\ln\left(x\right)}{\frac{1}{x}} \]
\[ u = \ln\left(x\right),\quad v = \frac{1}{x} \]
\[ u' = \frac{1}{x},\quad v' = \frac{-1}{x^{2}} \]
\[ f'(x) = \frac{\left(\frac{1}{x}\right)\left(\frac{1}{x}\right) - \left(\ln\left(x\right)\right)\left(\frac{-1}{x^{2}}\right)}{\left(\frac{1}{x}\right)^{2}} \]
\[ f'(x) = \frac{\frac{\frac{1}{x}}{x} - \ln\left(x\right) \frac{-1}{x^{2}}}{\frac{1}{x}^{2}} \]
\[ f''(x) = \frac{\left(\frac{\frac{-1}{x^{2}} x - \frac{1}{x}}{x^{2}} - \left(\frac{\frac{-1}{x^{2}}}{x} + \ln\left(x\right) \frac{-\left(\left(-2\right) x\right)}{\left(x^{2}\right)^{2}}\right)\right) \frac{1}{x}^{2} - \left(\frac{\frac{1}{x}}{x} - \ln\left(x\right) \frac{-1}{x^{2}}\right) 2 \frac{1}{x} \frac{-1}{x^{2}}}{\left(\frac{1}{x}^{2}\right)^{2}} \]Values of f and f' for ln(x) / (1 / x)
| x | f(x) | f'(x) |
|---|---|---|
| 0.5 | -0.34657359 | 0.30685282 |
| 1 | 0 | 1 |
| 2 | 1.3862944 | 1.6931472 |
| 3 | 3.2958369 | 2.0986123 |
Questions
What is the derivative of ln(x) / (1 / x)?
The derivative of is .
What is the second derivative of ln(x) / (1 / x)?
(((-1 / * x - 1 / x) / - (-1 / / x + ln(x) * -(-2x) / ()^2)) * (1 / x)^2 - (1 / x / x - ln(x) * -1 / ) * 2 * 1 / x * -1 / ) / ((1 / x)^2)^2.
Which rule do you use for ln(x) / (1 / x)?
The quotient rule.
What is the slope of ln(x) / (1 / x) at x = 1?
1.