Integral of $x^{-2}$

Q: What is the integral of x^(-2)?

The integral of x^-2 is x^-1-1 + C.

The integral of $x^{-2}$ is $\frac{x^{-1}}{-1} + C$ .

\int x^{-2}\,dx = \frac{x^{-1}}{-1} + C

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Graph of f(x) = x^(-2) with the area from 1 to 2 shaded. The shaded area equals the definite integral, about 0.5.

How to work it out

1
We want an antiderivative of f(x) = $x^{-2}$ .
$\int x^{-2}\,dx$
2
Method: power rule with a negative exponent.
3
That gives the antiderivative; add the constant C because any constant disappears when you differentiate:
$\int x^{-2}\,dx = \frac{x^{-1}}{-1} + C$
4
Check by differentiating the answer; you must get the original function back:
$\frac{d}{dx}\left[\frac{x^{-1}}{-1}\right] = x^{-2}$
5
As a definite integral, evaluate the antiderivative at both ends and subtract. Between 1 and 2:
$\int_{1}^{2} x^{-2}\,dx = \Big[\frac{x^{-1}}{-1}\Big]_{1}^{2} \approx 0.5$

LaTeX source of the formulas on this page

\[ \int x^{-2}\,dx = \frac{x^{-1}}{-1} + C \]
\[ \int x^{-2}\,dx \]
\[ \frac{d}{dx}\left[\frac{x^{-1}}{-1}\right] = x^{-2} \]
\[ \int_{1}^{2} x^{-2}\,dx = \Big[\frac{x^{-1}}{-1}\Big]_{1}^{2} \approx 0.5 \]

Definite integrals of the same function

Interval	Value
from 1 to 2	0.5
from 1 to 1.5	0.33333333

Questions

What is the integral of

x^{-2}

The integral of $x^{-2}$ is $\frac{x^{-1}}{-1} + C$ .

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

x^{-2}

from 1 to 2?

About 0.5.

Integral of x−2x^{-2}x−2

How to work it out

Definite integrals of the same function

Questions

More integrals

Integral of $x^{-2}$