maths.free › Calculus › Integrals

Integrals

Antiderivatives by substitution, parts and partial fractions.

Integration undoes differentiation. The solver shows which technique it uses (the power rule, a u-substitution, integration by parts, partial fractions) and the graph plots the antiderivative F against the integrand f, so you can see that F's slope is f.

Fungerat exempel · integral of x*e^x dx

Calculus · Integrals

Integrate x·e^(x)

\int x e^{x}\, dx

Steg för steg

  1. \int x e^{x}\, dx

    Find an antiderivative.

  2. u = x,\quad dv = e^{x}\, dx

    Integration by parts: ∫u dv = uv − ∫v du.

  3. du = 1\, dx,\quad v = e^{x}

    Differentiate u, integrate dv.

  4. \int x e^{x}\, dx = x e^{x} - \int e^{x}\, dx

    Apply the formula.

  5. \int e^{x}\, dx = e^{x}

    ∫ aᵘ du = aᵘ / ln a (for eˣ that is just eˣ).

  6. = x e^{x} - e^{x}

    Combine.

  7. F(x) = \left(x - 1\right) e^{x} + C

    Add the constant of integration.

Avslöja svaret
\left(x - 1\right) e^{x} + C

Nu är det din tur. Välj ett problem, skriv eller rita ditt eget. Varje steg, en bild, svaret dolt tills du frågar.

Fortsätt jobba.

Ett gratis konto lägger till anteckningar om varje lektion, en förteckning över vad du har avslutat, dina lösta problem på ett ställe, och en handledare du kan fråga om denna sida. Matematiken i sig är öppen för alla, inloggad eller inte.

Registrera dig Inloggning

Symboler som används här

Knacka på alla symboler för den fullständiga definitionen, en bild, och vad varje bokstav i den betyder.

Hur man: Integrals

  1. Find an antiderivative.
  2. Integration by parts: ∫u dv = uv − ∫v du.
  3. Differentiate u, integrate dv.
  4. Apply the formula.
  5. ∫ aᵘ du = aᵘ / ln a (for eˣ that is just eˣ).
  6. Combine.
  7. Add the constant of integration.

Frågor folk frågar

What is a derivative in one sentence?

The slope of the graph at a point, the rate at which the output is changing there. Speed is the derivative of position.

What is an integral in one sentence?

The accumulated total of a rate: the area under the curve. Distance travelled is the integral of speed.

Why are derivatives and integrals opposites?

That is the fundamental theorem of calculus: accumulating a rate and then measuring how fast the accumulation grows gets you back the rate. Integration undoes differentiation up to a constant.

When do I use substitution and when integration by parts?

Substitution when part of the integrand is the derivative of another part (u and du both present). Parts when the integrand is a product of two unrelated kinds of function, a polynomial times an exponential, log or trig function.

Mer information Calculus

LimitsDerivativesDefinite integralsTaylor seriesSeries and sumsMaxima and minimaThe chain ruleImplicit differentiationRelated rates and optimisationIntegration techniques: substitution, parts, partial fractionsApplications of integration: area, volume, arc lengthInfinite series and convergence tests