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Integral of eāˆ’8xe^{-8 x}

The integral of eāˆ’8xe^{-8 x} is āˆ’eāˆ’8x8+C\frac{-e^{-8 x}}{8} + C.

Graph of f(x) = exp(-8 * x) with the area from 0 to 1 shaded-0.4-0.20.20.40.60.811.21.41.620406080f(x)
Graph of f(x) = exp(-8 * x) with the area from 0 to 1 shaded. The shaded area equals the definite integral, about 0.12495807.

How to work it out

  1. 1

    We want an antiderivative of f(x) = exp(-8 * x).

    ∫eāˆ’8x dx\int e^{-8 x}\,dx
  2. 2

    Method: ∫eāˆ’kxe^{āˆ’kx} dx = āˆ’eāˆ’kxe^{āˆ’kx}/k.

  3. 3

    That gives the antiderivative; add the constant C because any constant disappears when you differentiate:

    ∫eāˆ’8x dx=āˆ’eāˆ’8x8+C\int e^{-8 x}\,dx = \frac{-e^{-8 x}}{8} + C
  4. 4

    Check by differentiating the answer; you must get the original function back:

    ddx[āˆ’eāˆ’8x8]=āˆ’((āˆ’64)e(āˆ’8)x)64\frac{d}{dx}\left[\frac{-e^{-8 x}}{8}\right] = \frac{-\left(\left(-64\right) e^{\left(-8\right) x}\right)}{64}
  5. 5

    As a definite integral, evaluate the antiderivative at both ends and subtract. Between 0 and 1:

    ∫01eāˆ’8x dx=[āˆ’eāˆ’8x8]01ā‰ˆ0.12495807\int_{0}^{1} e^{-8 x}\,dx = \Big[\frac{-e^{-8 x}}{8}\Big]_{0}^{1} \approx 0.12495807
LaTeX source of the formulas on this page
\[ \int e^{-8 x}\,dx = \frac{-e^{-8 x}}{8} + C \]
\[ \int e^{-8 x}\,dx \]
\[ \frac{d}{dx}\left[\frac{-e^{-8 x}}{8}\right] = \frac{-\left(\left(-64\right) e^{\left(-8\right) x}\right)}{64} \]
\[ \int_{0}^{1} e^{-8 x}\,dx = \Big[\frac{-e^{-8 x}}{8}\Big]_{0}^{1} \approx 0.12495807 \]

Definite integrals of the same function

IntervalValue
from 0 to 10.12495807
from 0 to 0.50.12271055

Questions

What is the integral of exp(-8 * x)?

The integral of eāˆ’8xe^{-8 x} is āˆ’eāˆ’8x8+C\frac{-e^{-8 x}}{8} + 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 exp(-8 * x) from 0 to 1?

About 0.12495807.

More integrals

    Integral of exp(-8 * x): -exp(-8 * x) / 8 + C (with steps) | WordGPT