Advanced Integration Techniques (Parts, Trig Sub & Partial Fractions)
Product rule reversal and algebraic decomposition of rational expressions
Visualize how Integration by Parts trades a difficult integral ∫ u dv for an easier one uv - ∫ v du.
1. The Geometry of Integration by Parts
Integration by parts splits an area in the (u, v) plane: the total bounding rectangle of area u(b)v(b) - u(a)v(a) decomposes into the horizontal integral ∫ u dv and the vertical integral ∫ v du.