Antiderivatives, Riemann Sums & The Fundamental Theorem of Calculus
Accumulating infinitesimal slices into total signed area
Vary partition count N from 3 to 60 to observe rectangle area sums converge toward the exact definite integral ∫_a^b f(x) dx.
1. The Fundamental Theorem of Calculus
FTC connects differentiation and integration as inverse operations: the rate of change of an accumulation function is the integrand itself, and definite integrals equal the net change in any antiderivative.