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Integration by parts

Integration by parts is used when the integrand is a product of two functions, and follows directly from the product rule for differentiation. We choose uu and v′v' so the remaining integral becomes simpler.

∫u v′ dx=uv−∫u′ v dx\int u\,v'\,dx = uv - \int u'\,v\,dxintegration by parts

Symbols

uudifferentiated
v′v'integrated to give v

Example

∫xex dx\displaystyle\int xe^x\,dx with u=x, v′=exu=x,\ v'=e^x: =xex−∫ex dx=(x−1)ex+C= xe^x - \int e^x\,dx = (x-1)e^x + C.

Choose uu so it gets simpler when differentiated (like xx), and v′v' easy to integrate (like exe^x).
Practise integration for free →

← Definite integral · Substitution →

Part of Calculus: Integration.