Integral of
The integral of is .
How to work it out
- 1
We want an antiderivative of f(x) = .
- 2
Method: power rule with a negative exponent.
- 3
That gives the antiderivative; add the constant C because any constant disappears when you differentiate:
- 4
Check by differentiating the answer; you must get the original function back:
- 5
As a definite integral, evaluate the antiderivative at both ends and subtract. Between 1 and 2:
LaTeX source of the formulas on this page
\[ \int x^{-4}\,dx = \frac{x^{-3}}{-3} + C \]
\[ \int x^{-4}\,dx \]
\[ \frac{d}{dx}\left[\frac{x^{-3}}{-3}\right] = \frac{9 x^{-4}}{9} \]
\[ \int_{1}^{2} x^{-4}\,dx = \Big[\frac{x^{-3}}{-3}\Big]_{1}^{2} \approx 0.29166667 \]Definite integrals of the same function
| Interval | Value |
|---|---|
| from 1 to 2 | 0.29166667 |
| from 1 to 1.5 | 0.2345679 |
Questions
What is the integral of ?
The integral of is .
Why do we add + C?
Every function F(x) + C has the same derivative, so the antiderivative is only defined up to a constant.
What is the integral of from 1 to 2?
About 0.29166667.