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
\[ \frac{d}{dx}\left[\frac{x^{3}}{\ln\left(x\right)}\right] = \frac{3 x^{2} \ln\left(x\right) - x^{3} \frac{1}{x}}{\ln\left(x\right)^{2}} \]
\[ f(x) = \frac{x^{3}}{\ln\left(x\right)} \]
\[ u = x^{3},\quad v = \ln\left(x\right) \]
\[ u' = 3 x^{2},\quad v' = \frac{1}{x} \]
\[ f'(x) = \frac{\left(3 x^{2}\right)\left(\ln\left(x\right)\right) - \left(x^{3}\right)\left(\frac{1}{x}\right)}{\left(\ln\left(x\right)\right)^{2}} \]
\[ f'(x) = \frac{3 x^{2} \ln\left(x\right) - x^{3} \frac{1}{x}}{\ln\left(x\right)^{2}} \]
\[ f''(x) = \frac{\left(6 x \ln\left(x\right) + 3 x^{2} \frac{1}{x} - \left(3 x^{2} \frac{1}{x} + x^{3} \frac{-1}{x^{2}}\right)\right) \ln\left(x\right)^{2} - \left(3 x^{2} \ln\left(x\right) - x^{3} \frac{1}{x}\right) 2 \ln\left(x\right) \frac{1}{x}}{\left(\ln\left(x\right)^{2}\right)^{2}} \]Values of f and f' for / ln(x)
| x | f(x) | f'(x) |
|---|---|---|
| 0.5 | -0.18033688 | -1.6023635 |
| 2 | 11.54156 | 8.9868646 |
| 3 | 24.576459 | 17.11964 |
Questions
What is the derivative of / ln(x)?
The derivative of is .
What is the second derivative of / ln(x)?
((6x * ln(x) + 3 * * 1 / x - (3 * * 1 / x + * -1 / )) * ln(x)^2 - (3 * * ln(x) - * 1 / x) * 2ln(x) * 1 / x) / (ln(x)^2)^2.
Which rule do you use for / ln(x)?
The quotient rule.
What is the slope of / ln(x) at x = 0.5?
-1.6023635.