What is it
Integration is the reverse process of differentiation, used to find the area under a curve and to reverse rates of change back into original quantities — covering standard integrals, integration by substitution, and integration by parts.
Why it matters
Integration completes the calculus toolkit alongside differentiation, and the two together — finding rates of change and accumulating them back up — are the foundation of physics, engineering, economics, and most quantitative university courses.
Exam tip
Always add the constant of integration '+ C' for indefinite integrals — forgetting it is a habitual, easily avoidable error that costs a mark on nearly every integration question if you're not deliberate about it.
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