Integral
An integral totals up a quantity that varies continuously, most often the area under a curve, by adding many thin approximating pieces and taking the limit as the pieces get thinner. The fundamental theorem of calculus states that integration and differentiation undo each other, so an area can be computed by finding a function whose derivative is the curve. That theorem is the reason calculus is one subject rather than two unrelated techniques.
Why it matters
Almost every accumulated quantity in science, distance from speed, mass from density, probability from a distribution, is an integral.
Also written: integrals, integration
Where it comes up
Read about Integral on Wikipedia
Sources
- Integral Wikipedia
- Fundamental theorem of calculus WikipediaThe result that connects the two halves of calculus. Read it directly after the integral article.
