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 chain rule.
- 2
Chain rule: differentiate the outer function, keep the inside, then multiply by the derivative of the inside. The inside is .
- 3
The outer function is sqrt(u); its derivative evaluated at g(x), times g'(x):
- 4
Simplify:
- 5
Differentiating once more gives the second derivative, which tells you about curvature:
LaTeX source of the formulas on this page
\[ \frac{d}{dx}\left[\sqrt{-x}\right] = \frac{-1}{2 \sqrt{-x}} \]
\[ f(x) = \sqrt{-x} \]
\[ g(x) = -x,\quad g'(x) = -1 \]
\[ f'(x) = \left[\frac{1}{2 \sqrt{u}}\right]_{u=g(x)} \cdot g'(x) \]
\[ f'(x) = \frac{-1}{2 \sqrt{-x}} \]
\[ f''(x) = \frac{-\left(\left(-2\right) \frac{-1}{2 \sqrt{-x}}\right)}{\left(2 \sqrt{-x}\right)^{2}} \]Values of f and f' for sqrt(-x)
| x | f(x) | f'(x) |
|---|---|---|
| -2 | 1.4142136 | -0.35355339 |
| -1 | 1 | -0.5 |
Questions
What is the derivative of sqrt(-x)?
The derivative of is .
What is the second derivative of sqrt(-x)?
-(-2 * -1 / (2sqrt(-x))) / (2sqrt(-x))^2.
Which rule do you use for sqrt(-x)?
The chain rule.
What is the slope of sqrt(-x) at x = -2?
-0.35355339.