DefinitionIntegration by parts is a method for integrating the product of two functions. It relies largely on the product rule of differentiation and completes the integration of a product of functions to a more simple integrations. The formula is ∫udv=uv−∫vdu where u and dv are parts of the original integrand This type is invaluable when differentiation causes some parts of the product to become easier. Example: ∫xexdx du=x dv=exdx Then, du=dx and v=ex. Integration by parts to ∫xexdx=xex−∫exdx=xex−ex+C=ex(x−1)+C