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Integral of eāˆ’7xe^{-7 x}

The integral of eāˆ’7xe^{-7 x} is āˆ’eāˆ’7x7+C\frac{-e^{-7 x}}{7} + C.

Graph of f(x) = exp(-7 * x) with the area from 0 to 1 shaded-0.4-0.20.20.40.60.811.21.41.610203040f(x)
Graph of f(x) = exp(-7 * x) with the area from 0 to 1 shaded. The shaded area equals the definite integral, about 0.14272687.

How to work it out

  1. 1

    We want an antiderivative of f(x) = exp(-7 * x).

    ∫eāˆ’7x dx\int e^{-7 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’7x dx=āˆ’eāˆ’7x7+C\int e^{-7 x}\,dx = \frac{-e^{-7 x}}{7} + C
  4. 4

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

    ddx[āˆ’eāˆ’7x7]=āˆ’((āˆ’49)e(āˆ’7)x)49\frac{d}{dx}\left[\frac{-e^{-7 x}}{7}\right] = \frac{-\left(\left(-49\right) e^{\left(-7\right) x}\right)}{49}
  5. 5

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

    ∫01eāˆ’7x dx=[āˆ’eāˆ’7x7]01ā‰ˆ0.14272687\int_{0}^{1} e^{-7 x}\,dx = \Big[\frac{-e^{-7 x}}{7}\Big]_{0}^{1} \approx 0.14272687
LaTeX source of the formulas on this page
\[ \int e^{-7 x}\,dx = \frac{-e^{-7 x}}{7} + C \]
\[ \int e^{-7 x}\,dx \]
\[ \frac{d}{dx}\left[\frac{-e^{-7 x}}{7}\right] = \frac{-\left(\left(-49\right) e^{\left(-7\right) x}\right)}{49} \]
\[ \int_{0}^{1} e^{-7 x}\,dx = \Big[\frac{-e^{-7 x}}{7}\Big]_{0}^{1} \approx 0.14272687 \]

Definite integrals of the same function

IntervalValue
from 0 to 10.14272687
from 0 to 0.50.13854323

Questions

What is the integral of exp(-7 * x)?

The integral of eāˆ’7xe^{-7 x} is āˆ’eāˆ’7x7+C\frac{-e^{-7 x}}{7} + 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(-7 * x) from 0 to 1?

About 0.14272687.

More integrals

    Integral of exp(-7 * x): -exp(-7 * x) / 7 + C (with steps) | WordGPT