Combine these techniques when an integrand is a product where one factor simplifies upon differentiation (for in integration by parts) and the other requires substitution to integrate (for ). This typically applies to polynomials multiplied by composite functions like , where you split the polynomial to facilitate the substitution needed for the antiderivative.
Conditions: The integrand is a product of two distinct types of functions.; One part reduces nicely when differentiated.; The other part requires a u-substitution to find its antiderivative.