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
\[ \frac{d}{dx}\left[\frac{\arctan\left(x\right)}{\ln\left(x\right)}\right] = \frac{\frac{\ln\left(x\right)}{1 + x^{2}} - \arctan\left(x\right) \frac{1}{x}}{\ln\left(x\right)^{2}} \]
\[ f(x) = \frac{\arctan\left(x\right)}{\ln\left(x\right)} \]
\[ u = \arctan\left(x\right),\quad v = \ln\left(x\right) \]
\[ u' = \frac{1}{1 + x^{2}},\quad v' = \frac{1}{x} \]
\[ f'(x) = \frac{\left(\frac{1}{1 + x^{2}}\right)\left(\ln\left(x\right)\right) - \left(\arctan\left(x\right)\right)\left(\frac{1}{x}\right)}{\left(\ln\left(x\right)\right)^{2}} \]
\[ f'(x) = \frac{\frac{\ln\left(x\right)}{1 + x^{2}} - \arctan\left(x\right) \frac{1}{x}}{\ln\left(x\right)^{2}} \]
\[ f''(x) = \frac{\left(\frac{\frac{1 + x^{2}}{x} - \ln\left(x\right) 2 x}{\left(1 + x^{2}\right)^{2}} - \left(\frac{\frac{1}{x}}{1 + x^{2}} + \arctan\left(x\right) \frac{-1}{x^{2}}\right)\right) \ln\left(x\right)^{2} - \left(\frac{\ln\left(x\right)}{1 + x^{2}} - \arctan\left(x\right) \frac{1}{x}\right) 2 \ln\left(x\right) \frac{1}{x}}{\left(\ln\left(x\right)^{2}\right)^{2}} \]Values of f and f' for atan(x) / ln(x)
| x | f(x) | f'(x) |
|---|---|---|
| 0.5 | -0.66890211 | -3.0841995 |
| 2 | 1.597278 | -0.86365349 |
| 3 | 1.1369305 | -0.25393564 |
Questions
What is the derivative of atan(x) / ln(x)?
The derivative of is .
What is the second derivative of atan(x) / ln(x)?
((((1 + ) / x - ln(x) * 2x) / (1 + )^2 - (1 / x / (1 + ) + atan(x) * -1 / )) * ln(x)^2 - (ln(x) / (1 + ) - atan(x) * 1 / x) * 2ln(x) * 1 / x) / (ln(x)^2)^2.
Which rule do you use for atan(x) / ln(x)?
The quotient rule.
What is the slope of atan(x) / ln(x) at x = 0.5?
-3.0841995.