∫ (1+x²)sin2x dx=∫ sin2x dx + ∫ x²sin2x dx=-(1/2)cos2x - (1/2)∫ x² d(cos2x)=-(1/2)cos2x - (1/2)x²cos2x + ∫ xcos2x dx=-(1/2)cos2x - (1/2)x²cos2x + (1/2)∫ x d(sin2x)=-(1/2...