Integration by Parts Math Example 1

Follow the full solution, then compare it with the other examples linked below.

Example 1

easy
Find โˆซxexโ€‰dx\displaystyle\int x e^x\,dx.

Solution

  1. 1
    LIATE: u=xu = x, dv=exโ€‰dxdv = e^x\,dx; then du=dxdu = dx, v=exv = e^x.
  2. 2
    โˆซxexโ€‰dx=xexโˆ’โˆซexโ€‰dx=xexโˆ’ex+C\int xe^x\,dx = xe^x - \int e^x\,dx = xe^x - e^x + C.
  3. 3
    Factor: ex(xโˆ’1)+Ce^x(x-1) + C.

Answer

ex(xโˆ’1)+Ce^x(x-1) + C
LIATE places algebraic before exponential, so u=xu = x. One IBP step reduces the remaining integral to something immediate.

About Integration by Parts

An integration technique based on the product rule: โˆซuโ€‰dv=uvโˆ’โˆซvโ€‰du\int u\,dv = uv - \int v\,du. Used when the integrand is a product of two functions.

Learn more about Integration by Parts โ†’

More Integration by Parts Examples